forked from OSchip/llvm-project
2637 lines
100 KiB
C++
2637 lines
100 KiB
C++
//===- InstCombineAndOrXor.cpp --------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the visitAnd, visitOr, and visitXor functions.
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//
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//===----------------------------------------------------------------------===//
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#include "InstCombineInternal.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/IR/ConstantRange.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
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#include "llvm/Transforms/Utils/Local.h"
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using namespace llvm;
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using namespace PatternMatch;
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#define DEBUG_TYPE "instcombine"
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static inline Value *dyn_castNotVal(Value *V) {
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// If this is not(not(x)) don't return that this is a not: we want the two
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// not's to be folded first.
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if (BinaryOperator::isNot(V)) {
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Value *Operand = BinaryOperator::getNotArgument(V);
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if (!IsFreeToInvert(Operand, Operand->hasOneUse()))
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return Operand;
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}
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// Constants can be considered to be not'ed values...
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if (ConstantInt *C = dyn_cast<ConstantInt>(V))
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return ConstantInt::get(C->getType(), ~C->getValue());
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return nullptr;
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}
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/// Similar to getICmpCode but for FCmpInst. This encodes a fcmp predicate into
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/// a four bit mask.
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static unsigned getFCmpCode(FCmpInst::Predicate CC) {
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assert(FCmpInst::FCMP_FALSE <= CC && CC <= FCmpInst::FCMP_TRUE &&
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"Unexpected FCmp predicate!");
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// Take advantage of the bit pattern of FCmpInst::Predicate here.
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// U L G E
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static_assert(FCmpInst::FCMP_FALSE == 0, ""); // 0 0 0 0
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static_assert(FCmpInst::FCMP_OEQ == 1, ""); // 0 0 0 1
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static_assert(FCmpInst::FCMP_OGT == 2, ""); // 0 0 1 0
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static_assert(FCmpInst::FCMP_OGE == 3, ""); // 0 0 1 1
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static_assert(FCmpInst::FCMP_OLT == 4, ""); // 0 1 0 0
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static_assert(FCmpInst::FCMP_OLE == 5, ""); // 0 1 0 1
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static_assert(FCmpInst::FCMP_ONE == 6, ""); // 0 1 1 0
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static_assert(FCmpInst::FCMP_ORD == 7, ""); // 0 1 1 1
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static_assert(FCmpInst::FCMP_UNO == 8, ""); // 1 0 0 0
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static_assert(FCmpInst::FCMP_UEQ == 9, ""); // 1 0 0 1
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static_assert(FCmpInst::FCMP_UGT == 10, ""); // 1 0 1 0
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static_assert(FCmpInst::FCMP_UGE == 11, ""); // 1 0 1 1
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static_assert(FCmpInst::FCMP_ULT == 12, ""); // 1 1 0 0
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static_assert(FCmpInst::FCMP_ULE == 13, ""); // 1 1 0 1
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static_assert(FCmpInst::FCMP_UNE == 14, ""); // 1 1 1 0
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static_assert(FCmpInst::FCMP_TRUE == 15, ""); // 1 1 1 1
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return CC;
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}
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/// This is the complement of getICmpCode, which turns an opcode and two
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/// operands into either a constant true or false, or a brand new ICmp
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/// instruction. The sign is passed in to determine which kind of predicate to
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/// use in the new icmp instruction.
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static Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
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InstCombiner::BuilderTy *Builder) {
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ICmpInst::Predicate NewPred;
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if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
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return NewConstant;
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return Builder->CreateICmp(NewPred, LHS, RHS);
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}
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/// This is the complement of getFCmpCode, which turns an opcode and two
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/// operands into either a FCmp instruction, or a true/false constant.
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static Value *getFCmpValue(unsigned Code, Value *LHS, Value *RHS,
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InstCombiner::BuilderTy *Builder) {
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const auto Pred = static_cast<FCmpInst::Predicate>(Code);
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assert(FCmpInst::FCMP_FALSE <= Pred && Pred <= FCmpInst::FCMP_TRUE &&
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"Unexpected FCmp predicate!");
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if (Pred == FCmpInst::FCMP_FALSE)
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return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
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if (Pred == FCmpInst::FCMP_TRUE)
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return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
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return Builder->CreateFCmp(Pred, LHS, RHS);
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}
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/// \brief Transform BITWISE_OP(BSWAP(A),BSWAP(B)) to BSWAP(BITWISE_OP(A, B))
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/// \param I Binary operator to transform.
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/// \return Pointer to node that must replace the original binary operator, or
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/// null pointer if no transformation was made.
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Value *InstCombiner::SimplifyBSwap(BinaryOperator &I) {
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IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
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// Can't do vectors.
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if (I.getType()->isVectorTy())
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return nullptr;
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// Can only do bitwise ops.
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if (!I.isBitwiseLogicOp())
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return nullptr;
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Value *OldLHS = I.getOperand(0);
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Value *OldRHS = I.getOperand(1);
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ConstantInt *ConstLHS = dyn_cast<ConstantInt>(OldLHS);
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ConstantInt *ConstRHS = dyn_cast<ConstantInt>(OldRHS);
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IntrinsicInst *IntrLHS = dyn_cast<IntrinsicInst>(OldLHS);
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IntrinsicInst *IntrRHS = dyn_cast<IntrinsicInst>(OldRHS);
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bool IsBswapLHS = (IntrLHS && IntrLHS->getIntrinsicID() == Intrinsic::bswap);
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bool IsBswapRHS = (IntrRHS && IntrRHS->getIntrinsicID() == Intrinsic::bswap);
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if (!IsBswapLHS && !IsBswapRHS)
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return nullptr;
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if (!IsBswapLHS && !ConstLHS)
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return nullptr;
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if (!IsBswapRHS && !ConstRHS)
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return nullptr;
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/// OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) )
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/// OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) )
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Value *NewLHS = IsBswapLHS ? IntrLHS->getOperand(0) :
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Builder->getInt(ConstLHS->getValue().byteSwap());
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Value *NewRHS = IsBswapRHS ? IntrRHS->getOperand(0) :
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Builder->getInt(ConstRHS->getValue().byteSwap());
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Value *BinOp = Builder->CreateBinOp(I.getOpcode(), NewLHS, NewRHS);
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Function *F = Intrinsic::getDeclaration(I.getModule(), Intrinsic::bswap, ITy);
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return Builder->CreateCall(F, BinOp);
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}
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/// This handles expressions of the form ((val OP C1) & C2). Where
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/// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'.
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Instruction *InstCombiner::OptAndOp(BinaryOperator *Op,
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ConstantInt *OpRHS,
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ConstantInt *AndRHS,
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BinaryOperator &TheAnd) {
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Value *X = Op->getOperand(0);
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Constant *Together = nullptr;
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if (!Op->isShift())
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Together = ConstantExpr::getAnd(AndRHS, OpRHS);
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switch (Op->getOpcode()) {
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default: break;
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case Instruction::Xor:
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if (Op->hasOneUse()) {
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// (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
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Value *And = Builder->CreateAnd(X, AndRHS);
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And->takeName(Op);
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return BinaryOperator::CreateXor(And, Together);
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}
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break;
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case Instruction::Or:
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if (Op->hasOneUse()){
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ConstantInt *TogetherCI = dyn_cast<ConstantInt>(Together);
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if (TogetherCI && !TogetherCI->isZero()){
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// (X | C1) & C2 --> (X & (C2^(C1&C2))) | C1
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// NOTE: This reduces the number of bits set in the & mask, which
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// can expose opportunities for store narrowing.
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Together = ConstantExpr::getXor(AndRHS, Together);
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Value *And = Builder->CreateAnd(X, Together);
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And->takeName(Op);
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return BinaryOperator::CreateOr(And, OpRHS);
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}
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}
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break;
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case Instruction::Add:
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if (Op->hasOneUse()) {
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// Adding a one to a single bit bit-field should be turned into an XOR
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// of the bit. First thing to check is to see if this AND is with a
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// single bit constant.
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const APInt &AndRHSV = AndRHS->getValue();
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// If there is only one bit set.
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if (AndRHSV.isPowerOf2()) {
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// Ok, at this point, we know that we are masking the result of the
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// ADD down to exactly one bit. If the constant we are adding has
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// no bits set below this bit, then we can eliminate the ADD.
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const APInt& AddRHS = OpRHS->getValue();
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// Check to see if any bits below the one bit set in AndRHSV are set.
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if ((AddRHS & (AndRHSV-1)) == 0) {
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// If not, the only thing that can effect the output of the AND is
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// the bit specified by AndRHSV. If that bit is set, the effect of
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// the XOR is to toggle the bit. If it is clear, then the ADD has
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// no effect.
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if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
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TheAnd.setOperand(0, X);
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return &TheAnd;
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} else {
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// Pull the XOR out of the AND.
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Value *NewAnd = Builder->CreateAnd(X, AndRHS);
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NewAnd->takeName(Op);
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return BinaryOperator::CreateXor(NewAnd, AndRHS);
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}
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}
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}
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}
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break;
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case Instruction::Shl: {
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// We know that the AND will not produce any of the bits shifted in, so if
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// the anded constant includes them, clear them now!
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//
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uint32_t BitWidth = AndRHS->getType()->getBitWidth();
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uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
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APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal));
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ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShlMask);
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if (CI->getValue() == ShlMask)
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// Masking out bits that the shift already masks.
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return replaceInstUsesWith(TheAnd, Op); // No need for the and.
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if (CI != AndRHS) { // Reducing bits set in and.
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TheAnd.setOperand(1, CI);
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return &TheAnd;
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}
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break;
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}
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case Instruction::LShr: {
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// We know that the AND will not produce any of the bits shifted in, so if
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// the anded constant includes them, clear them now! This only applies to
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// unsigned shifts, because a signed shr may bring in set bits!
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//
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uint32_t BitWidth = AndRHS->getType()->getBitWidth();
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uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
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APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
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ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShrMask);
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if (CI->getValue() == ShrMask)
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// Masking out bits that the shift already masks.
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return replaceInstUsesWith(TheAnd, Op);
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if (CI != AndRHS) {
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TheAnd.setOperand(1, CI); // Reduce bits set in and cst.
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return &TheAnd;
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}
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break;
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}
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case Instruction::AShr:
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// Signed shr.
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// See if this is shifting in some sign extension, then masking it out
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// with an and.
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if (Op->hasOneUse()) {
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uint32_t BitWidth = AndRHS->getType()->getBitWidth();
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uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
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APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
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Constant *C = Builder->getInt(AndRHS->getValue() & ShrMask);
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if (C == AndRHS) { // Masking out bits shifted in.
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// (Val ashr C1) & C2 -> (Val lshr C1) & C2
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// Make the argument unsigned.
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Value *ShVal = Op->getOperand(0);
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ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName());
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return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName());
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}
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}
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break;
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}
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return nullptr;
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}
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/// Emit a computation of: (V >= Lo && V < Hi) if Inside is true, otherwise
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/// (V < Lo || V >= Hi). This method expects that Lo <= Hi. IsSigned indicates
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/// whether to treat V, Lo, and Hi as signed or not.
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Value *InstCombiner::insertRangeTest(Value *V, const APInt &Lo, const APInt &Hi,
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bool isSigned, bool Inside) {
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assert((isSigned ? Lo.sle(Hi) : Lo.ule(Hi)) &&
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"Lo is not <= Hi in range emission code!");
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Type *Ty = V->getType();
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if (Lo == Hi)
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return Inside ? ConstantInt::getFalse(Ty) : ConstantInt::getTrue(Ty);
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// V >= Min && V < Hi --> V < Hi
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// V < Min || V >= Hi --> V >= Hi
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ICmpInst::Predicate Pred = Inside ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_UGE;
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if (isSigned ? Lo.isMinSignedValue() : Lo.isMinValue()) {
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Pred = isSigned ? ICmpInst::getSignedPredicate(Pred) : Pred;
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return Builder->CreateICmp(Pred, V, ConstantInt::get(Ty, Hi));
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}
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// V >= Lo && V < Hi --> V - Lo u< Hi - Lo
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// V < Lo || V >= Hi --> V - Lo u>= Hi - Lo
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Value *VMinusLo =
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Builder->CreateSub(V, ConstantInt::get(Ty, Lo), V->getName() + ".off");
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Constant *HiMinusLo = ConstantInt::get(Ty, Hi - Lo);
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return Builder->CreateICmp(Pred, VMinusLo, HiMinusLo);
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}
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/// Classify (icmp eq (A & B), C) and (icmp ne (A & B), C) as matching patterns
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/// that can be simplified.
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/// One of A and B is considered the mask. The other is the value. This is
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/// described as the "AMask" or "BMask" part of the enum. If the enum contains
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/// only "Mask", then both A and B can be considered masks. If A is the mask,
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/// then it was proven that (A & C) == C. This is trivial if C == A or C == 0.
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/// If both A and C are constants, this proof is also easy.
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/// For the following explanations, we assume that A is the mask.
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///
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/// "AllOnes" declares that the comparison is true only if (A & B) == A or all
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/// bits of A are set in B.
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/// Example: (icmp eq (A & 3), 3) -> AMask_AllOnes
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///
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/// "AllZeros" declares that the comparison is true only if (A & B) == 0 or all
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/// bits of A are cleared in B.
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/// Example: (icmp eq (A & 3), 0) -> Mask_AllZeroes
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///
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/// "Mixed" declares that (A & B) == C and C might or might not contain any
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/// number of one bits and zero bits.
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/// Example: (icmp eq (A & 3), 1) -> AMask_Mixed
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///
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/// "Not" means that in above descriptions "==" should be replaced by "!=".
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/// Example: (icmp ne (A & 3), 3) -> AMask_NotAllOnes
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///
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/// If the mask A contains a single bit, then the following is equivalent:
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/// (icmp eq (A & B), A) equals (icmp ne (A & B), 0)
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/// (icmp ne (A & B), A) equals (icmp eq (A & B), 0)
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enum MaskedICmpType {
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AMask_AllOnes = 1,
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AMask_NotAllOnes = 2,
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BMask_AllOnes = 4,
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BMask_NotAllOnes = 8,
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Mask_AllZeros = 16,
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Mask_NotAllZeros = 32,
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AMask_Mixed = 64,
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AMask_NotMixed = 128,
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BMask_Mixed = 256,
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BMask_NotMixed = 512
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};
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/// Return the set of patterns (from MaskedICmpType) that (icmp SCC (A & B), C)
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/// satisfies.
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static unsigned getMaskedICmpType(Value *A, Value *B, Value *C,
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ICmpInst::Predicate Pred) {
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ConstantInt *ACst = dyn_cast<ConstantInt>(A);
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ConstantInt *BCst = dyn_cast<ConstantInt>(B);
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ConstantInt *CCst = dyn_cast<ConstantInt>(C);
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bool IsEq = (Pred == ICmpInst::ICMP_EQ);
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bool IsAPow2 = (ACst && !ACst->isZero() && ACst->getValue().isPowerOf2());
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bool IsBPow2 = (BCst && !BCst->isZero() && BCst->getValue().isPowerOf2());
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unsigned MaskVal = 0;
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if (CCst && CCst->isZero()) {
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// if C is zero, then both A and B qualify as mask
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MaskVal |= (IsEq ? (Mask_AllZeros | AMask_Mixed | BMask_Mixed)
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: (Mask_NotAllZeros | AMask_NotMixed | BMask_NotMixed));
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if (IsAPow2)
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MaskVal |= (IsEq ? (AMask_NotAllOnes | AMask_NotMixed)
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: (AMask_AllOnes | AMask_Mixed));
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if (IsBPow2)
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MaskVal |= (IsEq ? (BMask_NotAllOnes | BMask_NotMixed)
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: (BMask_AllOnes | BMask_Mixed));
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return MaskVal;
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}
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if (A == C) {
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MaskVal |= (IsEq ? (AMask_AllOnes | AMask_Mixed)
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: (AMask_NotAllOnes | AMask_NotMixed));
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if (IsAPow2)
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MaskVal |= (IsEq ? (Mask_NotAllZeros | AMask_NotMixed)
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: (Mask_AllZeros | AMask_Mixed));
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} else if (ACst && CCst && ConstantExpr::getAnd(ACst, CCst) == CCst) {
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MaskVal |= (IsEq ? AMask_Mixed : AMask_NotMixed);
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}
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if (B == C) {
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MaskVal |= (IsEq ? (BMask_AllOnes | BMask_Mixed)
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: (BMask_NotAllOnes | BMask_NotMixed));
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if (IsBPow2)
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MaskVal |= (IsEq ? (Mask_NotAllZeros | BMask_NotMixed)
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: (Mask_AllZeros | BMask_Mixed));
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} else if (BCst && CCst && ConstantExpr::getAnd(BCst, CCst) == CCst) {
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MaskVal |= (IsEq ? BMask_Mixed : BMask_NotMixed);
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}
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return MaskVal;
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}
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/// Convert an analysis of a masked ICmp into its equivalent if all boolean
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/// operations had the opposite sense. Since each "NotXXX" flag (recording !=)
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/// is adjacent to the corresponding normal flag (recording ==), this just
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/// involves swapping those bits over.
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static unsigned conjugateICmpMask(unsigned Mask) {
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unsigned NewMask;
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NewMask = (Mask & (AMask_AllOnes | BMask_AllOnes | Mask_AllZeros |
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AMask_Mixed | BMask_Mixed))
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<< 1;
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NewMask |= (Mask & (AMask_NotAllOnes | BMask_NotAllOnes | Mask_NotAllZeros |
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AMask_NotMixed | BMask_NotMixed))
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>> 1;
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return NewMask;
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}
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/// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E).
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/// Return the set of pattern classes (from MaskedICmpType) that both LHS and
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/// RHS satisfy.
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static unsigned getMaskedTypeForICmpPair(Value *&A, Value *&B, Value *&C,
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Value *&D, Value *&E, ICmpInst *LHS,
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ICmpInst *RHS,
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ICmpInst::Predicate &PredL,
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ICmpInst::Predicate &PredR) {
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if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType())
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return 0;
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// vectors are not (yet?) supported
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|
if (LHS->getOperand(0)->getType()->isVectorTy())
|
|
return 0;
|
|
|
|
// Here comes the tricky part:
|
|
// LHS might be of the form L11 & L12 == X, X == L21 & L22,
|
|
// and L11 & L12 == L21 & L22. The same goes for RHS.
|
|
// Now we must find those components L** and R**, that are equal, so
|
|
// that we can extract the parameters A, B, C, D, and E for the canonical
|
|
// above.
|
|
Value *L1 = LHS->getOperand(0);
|
|
Value *L2 = LHS->getOperand(1);
|
|
Value *L11, *L12, *L21, *L22;
|
|
// Check whether the icmp can be decomposed into a bit test.
|
|
if (decomposeBitTestICmp(LHS, PredL, L11, L12, L2)) {
|
|
L21 = L22 = L1 = nullptr;
|
|
} else {
|
|
// Look for ANDs in the LHS icmp.
|
|
if (!L1->getType()->isIntegerTy()) {
|
|
// You can icmp pointers, for example. They really aren't masks.
|
|
L11 = L12 = nullptr;
|
|
} else if (!match(L1, m_And(m_Value(L11), m_Value(L12)))) {
|
|
// Any icmp can be viewed as being trivially masked; if it allows us to
|
|
// remove one, it's worth it.
|
|
L11 = L1;
|
|
L12 = Constant::getAllOnesValue(L1->getType());
|
|
}
|
|
|
|
if (!L2->getType()->isIntegerTy()) {
|
|
// You can icmp pointers, for example. They really aren't masks.
|
|
L21 = L22 = nullptr;
|
|
} else if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) {
|
|
L21 = L2;
|
|
L22 = Constant::getAllOnesValue(L2->getType());
|
|
}
|
|
}
|
|
|
|
// Bail if LHS was a icmp that can't be decomposed into an equality.
|
|
if (!ICmpInst::isEquality(PredL))
|
|
return 0;
|
|
|
|
Value *R1 = RHS->getOperand(0);
|
|
Value *R2 = RHS->getOperand(1);
|
|
Value *R11, *R12;
|
|
bool Ok = false;
|
|
if (decomposeBitTestICmp(RHS, PredR, R11, R12, R2)) {
|
|
if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
|
|
A = R11;
|
|
D = R12;
|
|
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
|
|
A = R12;
|
|
D = R11;
|
|
} else {
|
|
return 0;
|
|
}
|
|
E = R2;
|
|
R1 = nullptr;
|
|
Ok = true;
|
|
} else if (R1->getType()->isIntegerTy()) {
|
|
if (!match(R1, m_And(m_Value(R11), m_Value(R12)))) {
|
|
// As before, model no mask as a trivial mask if it'll let us do an
|
|
// optimization.
|
|
R11 = R1;
|
|
R12 = Constant::getAllOnesValue(R1->getType());
|
|
}
|
|
|
|
if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
|
|
A = R11;
|
|
D = R12;
|
|
E = R2;
|
|
Ok = true;
|
|
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
|
|
A = R12;
|
|
D = R11;
|
|
E = R2;
|
|
Ok = true;
|
|
}
|
|
}
|
|
|
|
// Bail if RHS was a icmp that can't be decomposed into an equality.
|
|
if (!ICmpInst::isEquality(PredR))
|
|
return 0;
|
|
|
|
// Look for ANDs on the right side of the RHS icmp.
|
|
if (!Ok && R2->getType()->isIntegerTy()) {
|
|
if (!match(R2, m_And(m_Value(R11), m_Value(R12)))) {
|
|
R11 = R2;
|
|
R12 = Constant::getAllOnesValue(R2->getType());
|
|
}
|
|
|
|
if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
|
|
A = R11;
|
|
D = R12;
|
|
E = R1;
|
|
Ok = true;
|
|
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
|
|
A = R12;
|
|
D = R11;
|
|
E = R1;
|
|
Ok = true;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
if (!Ok)
|
|
return 0;
|
|
|
|
if (L11 == A) {
|
|
B = L12;
|
|
C = L2;
|
|
} else if (L12 == A) {
|
|
B = L11;
|
|
C = L2;
|
|
} else if (L21 == A) {
|
|
B = L22;
|
|
C = L1;
|
|
} else if (L22 == A) {
|
|
B = L21;
|
|
C = L1;
|
|
}
|
|
|
|
unsigned LeftType = getMaskedICmpType(A, B, C, PredL);
|
|
unsigned RightType = getMaskedICmpType(A, D, E, PredR);
|
|
return LeftType & RightType;
|
|
}
|
|
|
|
/// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
|
|
/// into a single (icmp(A & X) ==/!= Y).
|
|
static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
|
|
llvm::InstCombiner::BuilderTy *Builder) {
|
|
Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
|
|
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
|
|
unsigned Mask =
|
|
getMaskedTypeForICmpPair(A, B, C, D, E, LHS, RHS, PredL, PredR);
|
|
if (Mask == 0)
|
|
return nullptr;
|
|
|
|
assert(ICmpInst::isEquality(PredL) && ICmpInst::isEquality(PredR) &&
|
|
"Expected equality predicates for masked type of icmps.");
|
|
|
|
// In full generality:
|
|
// (icmp (A & B) Op C) | (icmp (A & D) Op E)
|
|
// == ![ (icmp (A & B) !Op C) & (icmp (A & D) !Op E) ]
|
|
//
|
|
// If the latter can be converted into (icmp (A & X) Op Y) then the former is
|
|
// equivalent to (icmp (A & X) !Op Y).
|
|
//
|
|
// Therefore, we can pretend for the rest of this function that we're dealing
|
|
// with the conjunction, provided we flip the sense of any comparisons (both
|
|
// input and output).
|
|
|
|
// In most cases we're going to produce an EQ for the "&&" case.
|
|
ICmpInst::Predicate NewCC = IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
|
|
if (!IsAnd) {
|
|
// Convert the masking analysis into its equivalent with negated
|
|
// comparisons.
|
|
Mask = conjugateICmpMask(Mask);
|
|
}
|
|
|
|
if (Mask & Mask_AllZeros) {
|
|
// (icmp eq (A & B), 0) & (icmp eq (A & D), 0)
|
|
// -> (icmp eq (A & (B|D)), 0)
|
|
Value *NewOr = Builder->CreateOr(B, D);
|
|
Value *NewAnd = Builder->CreateAnd(A, NewOr);
|
|
// We can't use C as zero because we might actually handle
|
|
// (icmp ne (A & B), B) & (icmp ne (A & D), D)
|
|
// with B and D, having a single bit set.
|
|
Value *Zero = Constant::getNullValue(A->getType());
|
|
return Builder->CreateICmp(NewCC, NewAnd, Zero);
|
|
}
|
|
if (Mask & BMask_AllOnes) {
|
|
// (icmp eq (A & B), B) & (icmp eq (A & D), D)
|
|
// -> (icmp eq (A & (B|D)), (B|D))
|
|
Value *NewOr = Builder->CreateOr(B, D);
|
|
Value *NewAnd = Builder->CreateAnd(A, NewOr);
|
|
return Builder->CreateICmp(NewCC, NewAnd, NewOr);
|
|
}
|
|
if (Mask & AMask_AllOnes) {
|
|
// (icmp eq (A & B), A) & (icmp eq (A & D), A)
|
|
// -> (icmp eq (A & (B&D)), A)
|
|
Value *NewAnd1 = Builder->CreateAnd(B, D);
|
|
Value *NewAnd2 = Builder->CreateAnd(A, NewAnd1);
|
|
return Builder->CreateICmp(NewCC, NewAnd2, A);
|
|
}
|
|
|
|
// Remaining cases assume at least that B and D are constant, and depend on
|
|
// their actual values. This isn't strictly necessary, just a "handle the
|
|
// easy cases for now" decision.
|
|
ConstantInt *BCst = dyn_cast<ConstantInt>(B);
|
|
if (!BCst)
|
|
return nullptr;
|
|
ConstantInt *DCst = dyn_cast<ConstantInt>(D);
|
|
if (!DCst)
|
|
return nullptr;
|
|
|
|
if (Mask & (Mask_NotAllZeros | BMask_NotAllOnes)) {
|
|
// (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and
|
|
// (icmp ne (A & B), B) & (icmp ne (A & D), D)
|
|
// -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0)
|
|
// Only valid if one of the masks is a superset of the other (check "B&D" is
|
|
// the same as either B or D).
|
|
APInt NewMask = BCst->getValue() & DCst->getValue();
|
|
|
|
if (NewMask == BCst->getValue())
|
|
return LHS;
|
|
else if (NewMask == DCst->getValue())
|
|
return RHS;
|
|
}
|
|
|
|
if (Mask & AMask_NotAllOnes) {
|
|
// (icmp ne (A & B), B) & (icmp ne (A & D), D)
|
|
// -> (icmp ne (A & B), A) or (icmp ne (A & D), A)
|
|
// Only valid if one of the masks is a superset of the other (check "B|D" is
|
|
// the same as either B or D).
|
|
APInt NewMask = BCst->getValue() | DCst->getValue();
|
|
|
|
if (NewMask == BCst->getValue())
|
|
return LHS;
|
|
else if (NewMask == DCst->getValue())
|
|
return RHS;
|
|
}
|
|
|
|
if (Mask & BMask_Mixed) {
|
|
// (icmp eq (A & B), C) & (icmp eq (A & D), E)
|
|
// We already know that B & C == C && D & E == E.
|
|
// If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
|
|
// C and E, which are shared by both the mask B and the mask D, don't
|
|
// contradict, then we can transform to
|
|
// -> (icmp eq (A & (B|D)), (C|E))
|
|
// Currently, we only handle the case of B, C, D, and E being constant.
|
|
// We can't simply use C and E because we might actually handle
|
|
// (icmp ne (A & B), B) & (icmp eq (A & D), D)
|
|
// with B and D, having a single bit set.
|
|
ConstantInt *CCst = dyn_cast<ConstantInt>(C);
|
|
if (!CCst)
|
|
return nullptr;
|
|
ConstantInt *ECst = dyn_cast<ConstantInt>(E);
|
|
if (!ECst)
|
|
return nullptr;
|
|
if (PredL != NewCC)
|
|
CCst = cast<ConstantInt>(ConstantExpr::getXor(BCst, CCst));
|
|
if (PredR != NewCC)
|
|
ECst = cast<ConstantInt>(ConstantExpr::getXor(DCst, ECst));
|
|
|
|
// If there is a conflict, we should actually return a false for the
|
|
// whole construct.
|
|
if (((BCst->getValue() & DCst->getValue()) &
|
|
(CCst->getValue() ^ ECst->getValue())) != 0)
|
|
return ConstantInt::get(LHS->getType(), !IsAnd);
|
|
|
|
Value *NewOr1 = Builder->CreateOr(B, D);
|
|
Value *NewOr2 = ConstantExpr::getOr(CCst, ECst);
|
|
Value *NewAnd = Builder->CreateAnd(A, NewOr1);
|
|
return Builder->CreateICmp(NewCC, NewAnd, NewOr2);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Try to fold a signed range checked with lower bound 0 to an unsigned icmp.
|
|
/// Example: (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
|
|
/// If \p Inverted is true then the check is for the inverted range, e.g.
|
|
/// (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
|
|
Value *InstCombiner::simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1,
|
|
bool Inverted) {
|
|
// Check the lower range comparison, e.g. x >= 0
|
|
// InstCombine already ensured that if there is a constant it's on the RHS.
|
|
ConstantInt *RangeStart = dyn_cast<ConstantInt>(Cmp0->getOperand(1));
|
|
if (!RangeStart)
|
|
return nullptr;
|
|
|
|
ICmpInst::Predicate Pred0 = (Inverted ? Cmp0->getInversePredicate() :
|
|
Cmp0->getPredicate());
|
|
|
|
// Accept x > -1 or x >= 0 (after potentially inverting the predicate).
|
|
if (!((Pred0 == ICmpInst::ICMP_SGT && RangeStart->isMinusOne()) ||
|
|
(Pred0 == ICmpInst::ICMP_SGE && RangeStart->isZero())))
|
|
return nullptr;
|
|
|
|
ICmpInst::Predicate Pred1 = (Inverted ? Cmp1->getInversePredicate() :
|
|
Cmp1->getPredicate());
|
|
|
|
Value *Input = Cmp0->getOperand(0);
|
|
Value *RangeEnd;
|
|
if (Cmp1->getOperand(0) == Input) {
|
|
// For the upper range compare we have: icmp x, n
|
|
RangeEnd = Cmp1->getOperand(1);
|
|
} else if (Cmp1->getOperand(1) == Input) {
|
|
// For the upper range compare we have: icmp n, x
|
|
RangeEnd = Cmp1->getOperand(0);
|
|
Pred1 = ICmpInst::getSwappedPredicate(Pred1);
|
|
} else {
|
|
return nullptr;
|
|
}
|
|
|
|
// Check the upper range comparison, e.g. x < n
|
|
ICmpInst::Predicate NewPred;
|
|
switch (Pred1) {
|
|
case ICmpInst::ICMP_SLT: NewPred = ICmpInst::ICMP_ULT; break;
|
|
case ICmpInst::ICMP_SLE: NewPred = ICmpInst::ICMP_ULE; break;
|
|
default: return nullptr;
|
|
}
|
|
|
|
// This simplification is only valid if the upper range is not negative.
|
|
bool IsNegative, IsNotNegative;
|
|
ComputeSignBit(RangeEnd, IsNotNegative, IsNegative, /*Depth=*/0, Cmp1);
|
|
if (!IsNotNegative)
|
|
return nullptr;
|
|
|
|
if (Inverted)
|
|
NewPred = ICmpInst::getInversePredicate(NewPred);
|
|
|
|
return Builder->CreateICmp(NewPred, Input, RangeEnd);
|
|
}
|
|
|
|
static Value *
|
|
foldAndOrOfEqualityCmpsWithConstants(ICmpInst *LHS, ICmpInst *RHS,
|
|
bool JoinedByAnd,
|
|
InstCombiner::BuilderTy *Builder) {
|
|
Value *X = LHS->getOperand(0);
|
|
if (X != RHS->getOperand(0))
|
|
return nullptr;
|
|
|
|
const APInt *C1, *C2;
|
|
if (!match(LHS->getOperand(1), m_APInt(C1)) ||
|
|
!match(RHS->getOperand(1), m_APInt(C2)))
|
|
return nullptr;
|
|
|
|
// We only handle (X != C1 && X != C2) and (X == C1 || X == C2).
|
|
ICmpInst::Predicate Pred = LHS->getPredicate();
|
|
if (Pred != RHS->getPredicate())
|
|
return nullptr;
|
|
if (JoinedByAnd && Pred != ICmpInst::ICMP_NE)
|
|
return nullptr;
|
|
if (!JoinedByAnd && Pred != ICmpInst::ICMP_EQ)
|
|
return nullptr;
|
|
|
|
// The larger unsigned constant goes on the right.
|
|
if (C1->ugt(*C2))
|
|
std::swap(C1, C2);
|
|
|
|
APInt Xor = *C1 ^ *C2;
|
|
if (Xor.isPowerOf2()) {
|
|
// If LHSC and RHSC differ by only one bit, then set that bit in X and
|
|
// compare against the larger constant:
|
|
// (X == C1 || X == C2) --> (X | (C1 ^ C2)) == C2
|
|
// (X != C1 && X != C2) --> (X | (C1 ^ C2)) != C2
|
|
// We choose an 'or' with a Pow2 constant rather than the inverse mask with
|
|
// 'and' because that may lead to smaller codegen from a smaller constant.
|
|
Value *Or = Builder->CreateOr(X, ConstantInt::get(X->getType(), Xor));
|
|
return Builder->CreateICmp(Pred, Or, ConstantInt::get(X->getType(), *C2));
|
|
}
|
|
|
|
// Special case: get the ordering right when the values wrap around zero.
|
|
// Ie, we assumed the constants were unsigned when swapping earlier.
|
|
if (*C1 == 0 && C2->isAllOnesValue())
|
|
std::swap(C1, C2);
|
|
|
|
if (*C1 == *C2 - 1) {
|
|
// (X == 13 || X == 14) --> X - 13 <=u 1
|
|
// (X != 13 && X != 14) --> X - 13 >u 1
|
|
// An 'add' is the canonical IR form, so favor that over a 'sub'.
|
|
Value *Add = Builder->CreateAdd(X, ConstantInt::get(X->getType(), -(*C1)));
|
|
auto NewPred = JoinedByAnd ? ICmpInst::ICMP_UGT : ICmpInst::ICMP_ULE;
|
|
return Builder->CreateICmp(NewPred, Add, ConstantInt::get(X->getType(), 1));
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Fold (icmp)&(icmp) if possible.
|
|
Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
|
|
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
|
|
|
|
// (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
|
|
if (PredicatesFoldable(PredL, PredR)) {
|
|
if (LHS->getOperand(0) == RHS->getOperand(1) &&
|
|
LHS->getOperand(1) == RHS->getOperand(0))
|
|
LHS->swapOperands();
|
|
if (LHS->getOperand(0) == RHS->getOperand(0) &&
|
|
LHS->getOperand(1) == RHS->getOperand(1)) {
|
|
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
|
|
unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
|
|
bool isSigned = LHS->isSigned() || RHS->isSigned();
|
|
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
|
|
}
|
|
}
|
|
|
|
// handle (roughly): (icmp eq (A & B), C) & (icmp eq (A & D), E)
|
|
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, true, Builder))
|
|
return V;
|
|
|
|
// E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
|
|
if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/false))
|
|
return V;
|
|
|
|
// E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n
|
|
if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/false))
|
|
return V;
|
|
|
|
if (Value *V = foldAndOrOfEqualityCmpsWithConstants(LHS, RHS, true, Builder))
|
|
return V;
|
|
|
|
// This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
|
|
Value *LHS0 = LHS->getOperand(0), *RHS0 = RHS->getOperand(0);
|
|
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
|
|
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
|
|
if (!LHSC || !RHSC)
|
|
return nullptr;
|
|
|
|
if (LHSC == RHSC && PredL == PredR) {
|
|
// (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
|
|
// where C is a power of 2 or
|
|
// (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
|
|
if ((PredL == ICmpInst::ICMP_ULT && LHSC->getValue().isPowerOf2()) ||
|
|
(PredL == ICmpInst::ICMP_EQ && LHSC->isZero())) {
|
|
Value *NewOr = Builder->CreateOr(LHS0, RHS0);
|
|
return Builder->CreateICmp(PredL, NewOr, LHSC);
|
|
}
|
|
}
|
|
|
|
// (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
|
|
// where CMAX is the all ones value for the truncated type,
|
|
// iff the lower bits of C2 and CA are zero.
|
|
if (PredL == ICmpInst::ICMP_EQ && PredL == PredR && LHS->hasOneUse() &&
|
|
RHS->hasOneUse()) {
|
|
Value *V;
|
|
ConstantInt *AndC, *SmallC = nullptr, *BigC = nullptr;
|
|
|
|
// (trunc x) == C1 & (and x, CA) == C2
|
|
// (and x, CA) == C2 & (trunc x) == C1
|
|
if (match(RHS0, m_Trunc(m_Value(V))) &&
|
|
match(LHS0, m_And(m_Specific(V), m_ConstantInt(AndC)))) {
|
|
SmallC = RHSC;
|
|
BigC = LHSC;
|
|
} else if (match(LHS0, m_Trunc(m_Value(V))) &&
|
|
match(RHS0, m_And(m_Specific(V), m_ConstantInt(AndC)))) {
|
|
SmallC = LHSC;
|
|
BigC = RHSC;
|
|
}
|
|
|
|
if (SmallC && BigC) {
|
|
unsigned BigBitSize = BigC->getType()->getBitWidth();
|
|
unsigned SmallBitSize = SmallC->getType()->getBitWidth();
|
|
|
|
// Check that the low bits are zero.
|
|
APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
|
|
if ((Low & AndC->getValue()) == 0 && (Low & BigC->getValue()) == 0) {
|
|
Value *NewAnd = Builder->CreateAnd(V, Low | AndC->getValue());
|
|
APInt N = SmallC->getValue().zext(BigBitSize) | BigC->getValue();
|
|
Value *NewVal = ConstantInt::get(AndC->getType()->getContext(), N);
|
|
return Builder->CreateICmp(PredL, NewAnd, NewVal);
|
|
}
|
|
}
|
|
}
|
|
|
|
// From here on, we only handle:
|
|
// (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
|
|
if (LHS0 != RHS0)
|
|
return nullptr;
|
|
|
|
// ICMP_[US][GL]E X, C is folded to ICMP_[US][GL]T elsewhere.
|
|
if (PredL == ICmpInst::ICMP_UGE || PredL == ICmpInst::ICMP_ULE ||
|
|
PredR == ICmpInst::ICMP_UGE || PredR == ICmpInst::ICMP_ULE ||
|
|
PredL == ICmpInst::ICMP_SGE || PredL == ICmpInst::ICMP_SLE ||
|
|
PredR == ICmpInst::ICMP_SGE || PredR == ICmpInst::ICMP_SLE)
|
|
return nullptr;
|
|
|
|
// We can't fold (ugt x, C) & (sgt x, C2).
|
|
if (!PredicatesFoldable(PredL, PredR))
|
|
return nullptr;
|
|
|
|
// Ensure that the larger constant is on the RHS.
|
|
bool ShouldSwap;
|
|
if (CmpInst::isSigned(PredL) ||
|
|
(ICmpInst::isEquality(PredL) && CmpInst::isSigned(PredR)))
|
|
ShouldSwap = LHSC->getValue().sgt(RHSC->getValue());
|
|
else
|
|
ShouldSwap = LHSC->getValue().ugt(RHSC->getValue());
|
|
|
|
if (ShouldSwap) {
|
|
std::swap(LHS, RHS);
|
|
std::swap(LHSC, RHSC);
|
|
std::swap(PredL, PredR);
|
|
}
|
|
|
|
// At this point, we know we have two icmp instructions
|
|
// comparing a value against two constants and and'ing the result
|
|
// together. Because of the above check, we know that we only have
|
|
// icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know
|
|
// (from the icmp folding check above), that the two constants
|
|
// are not equal and that the larger constant is on the RHS
|
|
assert(LHSC != RHSC && "Compares not folded above?");
|
|
|
|
switch (PredL) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_NE:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_ULT:
|
|
if (LHSC == SubOne(RHSC)) // (X != 13 & X u< 14) -> X < 13
|
|
return Builder->CreateICmpULT(LHS0, LHSC);
|
|
if (LHSC->isNullValue()) // (X != 0 & X u< 14) -> X-1 u< 13
|
|
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
|
|
false, true);
|
|
break; // (X != 13 & X u< 15) -> no change
|
|
case ICmpInst::ICMP_SLT:
|
|
if (LHSC == SubOne(RHSC)) // (X != 13 & X s< 14) -> X < 13
|
|
return Builder->CreateICmpSLT(LHS0, LHSC);
|
|
break; // (X != 13 & X s< 15) -> no change
|
|
case ICmpInst::ICMP_NE:
|
|
// Potential folds for this case should already be handled.
|
|
break;
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_UGT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_NE:
|
|
if (RHSC == AddOne(LHSC)) // (X u> 13 & X != 14) -> X u> 14
|
|
return Builder->CreateICmp(PredL, LHS0, RHSC);
|
|
break; // (X u> 13 & X != 15) -> no change
|
|
case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
|
|
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
|
|
false, true);
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_SGT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_NE:
|
|
if (RHSC == AddOne(LHSC)) // (X s> 13 & X != 14) -> X s> 14
|
|
return Builder->CreateICmp(PredL, LHS0, RHSC);
|
|
break; // (X s> 13 & X != 15) -> no change
|
|
case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
|
|
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(), true,
|
|
true);
|
|
}
|
|
break;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Optimize (fcmp)&(fcmp). NOTE: Unlike the rest of instcombine, this returns
|
|
/// a Value which should already be inserted into the function.
|
|
Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
|
|
Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
|
|
Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
|
|
FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
|
|
|
|
if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
|
|
// Swap RHS operands to match LHS.
|
|
Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
|
|
std::swap(Op1LHS, Op1RHS);
|
|
}
|
|
|
|
// Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
|
|
// Suppose the relation between x and y is R, where R is one of
|
|
// U(1000), L(0100), G(0010) or E(0001), and CC0 and CC1 are the bitmasks for
|
|
// testing the desired relations.
|
|
//
|
|
// Since (R & CC0) and (R & CC1) are either R or 0, we actually have this:
|
|
// bool(R & CC0) && bool(R & CC1)
|
|
// = bool((R & CC0) & (R & CC1))
|
|
// = bool(R & (CC0 & CC1)) <= by re-association, commutation, and idempotency
|
|
if (Op0LHS == Op1LHS && Op0RHS == Op1RHS)
|
|
return getFCmpValue(getFCmpCode(Op0CC) & getFCmpCode(Op1CC), Op0LHS, Op0RHS,
|
|
Builder);
|
|
|
|
if (LHS->getPredicate() == FCmpInst::FCMP_ORD &&
|
|
RHS->getPredicate() == FCmpInst::FCMP_ORD) {
|
|
if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType())
|
|
return nullptr;
|
|
|
|
// (fcmp ord x, c) & (fcmp ord y, c) -> (fcmp ord x, y)
|
|
if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
|
|
if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
|
|
// If either of the constants are nans, then the whole thing returns
|
|
// false.
|
|
if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
|
|
return Builder->getFalse();
|
|
return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
|
|
}
|
|
|
|
// Handle vector zeros. This occurs because the canonical form of
|
|
// "fcmp ord x,x" is "fcmp ord x, 0".
|
|
if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
|
|
isa<ConstantAggregateZero>(RHS->getOperand(1)))
|
|
return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
|
|
return nullptr;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Match De Morgan's Laws:
|
|
/// (~A & ~B) == (~(A | B))
|
|
/// (~A | ~B) == (~(A & B))
|
|
static Instruction *matchDeMorgansLaws(BinaryOperator &I,
|
|
InstCombiner::BuilderTy *Builder) {
|
|
auto Opcode = I.getOpcode();
|
|
assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
|
|
"Trying to match De Morgan's Laws with something other than and/or");
|
|
// Flip the logic operation.
|
|
if (Opcode == Instruction::And)
|
|
Opcode = Instruction::Or;
|
|
else
|
|
Opcode = Instruction::And;
|
|
|
|
Value *Op0 = I.getOperand(0);
|
|
Value *Op1 = I.getOperand(1);
|
|
// TODO: Use pattern matchers instead of dyn_cast.
|
|
if (Value *Op0NotVal = dyn_castNotVal(Op0))
|
|
if (Value *Op1NotVal = dyn_castNotVal(Op1))
|
|
if (Op0->hasOneUse() && Op1->hasOneUse()) {
|
|
Value *LogicOp = Builder->CreateBinOp(Opcode, Op0NotVal, Op1NotVal,
|
|
I.getName() + ".demorgan");
|
|
return BinaryOperator::CreateNot(LogicOp);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
bool InstCombiner::shouldOptimizeCast(CastInst *CI) {
|
|
Value *CastSrc = CI->getOperand(0);
|
|
|
|
// Noop casts and casts of constants should be eliminated trivially.
|
|
if (CI->getSrcTy() == CI->getDestTy() || isa<Constant>(CastSrc))
|
|
return false;
|
|
|
|
// If this cast is paired with another cast that can be eliminated, we prefer
|
|
// to have it eliminated.
|
|
if (const auto *PrecedingCI = dyn_cast<CastInst>(CastSrc))
|
|
if (isEliminableCastPair(PrecedingCI, CI))
|
|
return false;
|
|
|
|
// If this is a vector sext from a compare, then we don't want to break the
|
|
// idiom where each element of the extended vector is either zero or all ones.
|
|
if (CI->getOpcode() == Instruction::SExt &&
|
|
isa<CmpInst>(CastSrc) && CI->getDestTy()->isVectorTy())
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/// Fold {and,or,xor} (cast X), C.
|
|
static Instruction *foldLogicCastConstant(BinaryOperator &Logic, CastInst *Cast,
|
|
InstCombiner::BuilderTy *Builder) {
|
|
Constant *C;
|
|
if (!match(Logic.getOperand(1), m_Constant(C)))
|
|
return nullptr;
|
|
|
|
auto LogicOpc = Logic.getOpcode();
|
|
Type *DestTy = Logic.getType();
|
|
Type *SrcTy = Cast->getSrcTy();
|
|
|
|
// If the first operand is bitcast, move the logic operation ahead of the
|
|
// bitcast (do the logic operation in the original type). This can eliminate
|
|
// bitcasts and allow combines that would otherwise be impeded by the bitcast.
|
|
Value *X;
|
|
if (match(Cast, m_BitCast(m_Value(X)))) {
|
|
Value *NewConstant = ConstantExpr::getBitCast(C, SrcTy);
|
|
Value *NewOp = Builder->CreateBinOp(LogicOpc, X, NewConstant);
|
|
return CastInst::CreateBitOrPointerCast(NewOp, DestTy);
|
|
}
|
|
|
|
// Similarly, move the logic operation ahead of a zext if the constant is
|
|
// unchanged in the smaller source type. Performing the logic in a smaller
|
|
// type may provide more information to later folds, and the smaller logic
|
|
// instruction may be cheaper (particularly in the case of vectors).
|
|
if (match(Cast, m_OneUse(m_ZExt(m_Value(X))))) {
|
|
Constant *TruncC = ConstantExpr::getTrunc(C, SrcTy);
|
|
Constant *ZextTruncC = ConstantExpr::getZExt(TruncC, DestTy);
|
|
if (ZextTruncC == C) {
|
|
// LogicOpc (zext X), C --> zext (LogicOpc X, C)
|
|
Value *NewOp = Builder->CreateBinOp(LogicOpc, X, TruncC);
|
|
return new ZExtInst(NewOp, DestTy);
|
|
}
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Fold {and,or,xor} (cast X), Y.
|
|
Instruction *InstCombiner::foldCastedBitwiseLogic(BinaryOperator &I) {
|
|
auto LogicOpc = I.getOpcode();
|
|
assert(I.isBitwiseLogicOp() && "Unexpected opcode for bitwise logic folding");
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
CastInst *Cast0 = dyn_cast<CastInst>(Op0);
|
|
if (!Cast0)
|
|
return nullptr;
|
|
|
|
// This must be a cast from an integer or integer vector source type to allow
|
|
// transformation of the logic operation to the source type.
|
|
Type *DestTy = I.getType();
|
|
Type *SrcTy = Cast0->getSrcTy();
|
|
if (!SrcTy->isIntOrIntVectorTy())
|
|
return nullptr;
|
|
|
|
if (Instruction *Ret = foldLogicCastConstant(I, Cast0, Builder))
|
|
return Ret;
|
|
|
|
CastInst *Cast1 = dyn_cast<CastInst>(Op1);
|
|
if (!Cast1)
|
|
return nullptr;
|
|
|
|
// Both operands of the logic operation are casts. The casts must be of the
|
|
// same type for reduction.
|
|
auto CastOpcode = Cast0->getOpcode();
|
|
if (CastOpcode != Cast1->getOpcode() || SrcTy != Cast1->getSrcTy())
|
|
return nullptr;
|
|
|
|
Value *Cast0Src = Cast0->getOperand(0);
|
|
Value *Cast1Src = Cast1->getOperand(0);
|
|
|
|
// fold logic(cast(A), cast(B)) -> cast(logic(A, B))
|
|
if (shouldOptimizeCast(Cast0) && shouldOptimizeCast(Cast1)) {
|
|
Value *NewOp = Builder->CreateBinOp(LogicOpc, Cast0Src, Cast1Src,
|
|
I.getName());
|
|
return CastInst::Create(CastOpcode, NewOp, DestTy);
|
|
}
|
|
|
|
// For now, only 'and'/'or' have optimizations after this.
|
|
if (LogicOpc == Instruction::Xor)
|
|
return nullptr;
|
|
|
|
// If this is logic(cast(icmp), cast(icmp)), try to fold this even if the
|
|
// cast is otherwise not optimizable. This happens for vector sexts.
|
|
ICmpInst *ICmp0 = dyn_cast<ICmpInst>(Cast0Src);
|
|
ICmpInst *ICmp1 = dyn_cast<ICmpInst>(Cast1Src);
|
|
if (ICmp0 && ICmp1) {
|
|
Value *Res = LogicOpc == Instruction::And ? FoldAndOfICmps(ICmp0, ICmp1)
|
|
: FoldOrOfICmps(ICmp0, ICmp1, &I);
|
|
if (Res)
|
|
return CastInst::Create(CastOpcode, Res, DestTy);
|
|
return nullptr;
|
|
}
|
|
|
|
// If this is logic(cast(fcmp), cast(fcmp)), try to fold this even if the
|
|
// cast is otherwise not optimizable. This happens for vector sexts.
|
|
FCmpInst *FCmp0 = dyn_cast<FCmpInst>(Cast0Src);
|
|
FCmpInst *FCmp1 = dyn_cast<FCmpInst>(Cast1Src);
|
|
if (FCmp0 && FCmp1) {
|
|
Value *Res = LogicOpc == Instruction::And ? FoldAndOfFCmps(FCmp0, FCmp1)
|
|
: FoldOrOfFCmps(FCmp0, FCmp1);
|
|
if (Res)
|
|
return CastInst::Create(CastOpcode, Res, DestTy);
|
|
return nullptr;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
static Instruction *foldBoolSextMaskToSelect(BinaryOperator &I) {
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
// Canonicalize SExt or Not to the LHS
|
|
if (match(Op1, m_SExt(m_Value())) || match(Op1, m_Not(m_Value()))) {
|
|
std::swap(Op0, Op1);
|
|
}
|
|
|
|
// Fold (and (sext bool to A), B) --> (select bool, B, 0)
|
|
Value *X = nullptr;
|
|
if (match(Op0, m_SExt(m_Value(X))) &&
|
|
X->getType()->getScalarType()->isIntegerTy(1)) {
|
|
Value *Zero = Constant::getNullValue(Op1->getType());
|
|
return SelectInst::Create(X, Op1, Zero);
|
|
}
|
|
|
|
// Fold (and ~(sext bool to A), B) --> (select bool, 0, B)
|
|
if (match(Op0, m_Not(m_SExt(m_Value(X)))) &&
|
|
X->getType()->getScalarType()->isIntegerTy(1)) {
|
|
Value *Zero = Constant::getNullValue(Op0->getType());
|
|
return SelectInst::Create(X, Zero, Op1);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
static Instruction *foldAndToXor(BinaryOperator &I,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
assert(I.getOpcode() == Instruction::And);
|
|
Value *Op0 = I.getOperand(0);
|
|
Value *Op1 = I.getOperand(1);
|
|
Value *A, *B;
|
|
|
|
// Operand complexity canonicalization guarantees that the 'or' is Op0.
|
|
// (A | B) & ~(A & B) --> A ^ B
|
|
// (A | B) & ~(B & A) --> A ^ B
|
|
if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_Not(m_c_And(m_Specific(A), m_Specific(B)))))
|
|
return BinaryOperator::CreateXor(A, B);
|
|
|
|
// (A | ~B) & (~A | B) --> ~(A ^ B)
|
|
// (A | ~B) & (B | ~A) --> ~(A ^ B)
|
|
// (~B | A) & (~A | B) --> ~(A ^ B)
|
|
// (~B | A) & (B | ~A) --> ~(A ^ B)
|
|
if (match(Op0, m_c_Or(m_Value(A), m_Not(m_Value(B)))) &&
|
|
match(Op1, m_c_Or(m_Not(m_Specific(A)), m_Specific(B))))
|
|
return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
static Instruction *foldOrToXor(BinaryOperator &I,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
assert(I.getOpcode() == Instruction::Or);
|
|
Value *Op0 = I.getOperand(0);
|
|
Value *Op1 = I.getOperand(1);
|
|
Value *A, *B;
|
|
|
|
// Operand complexity canonicalization guarantees that the 'and' is Op0.
|
|
// (A & B) | ~(A | B) --> ~(A ^ B)
|
|
// (A & B) | ~(B | A) --> ~(A ^ B)
|
|
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
|
|
return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
|
|
|
|
// (A & ~B) | (~A & B) --> A ^ B
|
|
// (A & ~B) | (B & ~A) --> A ^ B
|
|
// (~B & A) | (~A & B) --> A ^ B
|
|
// (~B & A) | (B & ~A) --> A ^ B
|
|
if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
|
|
match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B))))
|
|
return BinaryOperator::CreateXor(A, B);
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
|
|
// here. We should standardize that construct where it is needed or choose some
|
|
// other way to ensure that commutated variants of patterns are not missed.
|
|
Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
|
|
bool Changed = SimplifyAssociativeOrCommutative(I);
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifyVectorOp(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyAndInst(Op0, Op1, SQ))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
// See if we can simplify any instructions used by the instruction whose sole
|
|
// purpose is to compute bits we don't care about.
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
return &I;
|
|
|
|
// Do this before using distributive laws to catch simple and/or/not patterns.
|
|
if (Instruction *Xor = foldAndToXor(I, *Builder))
|
|
return Xor;
|
|
|
|
// (A|B)&(A|C) -> A|(B&C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyBSwap(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
|
|
const APInt &AndRHSMask = AndRHS->getValue();
|
|
|
|
// Optimize a variety of ((val OP C1) & C2) combinations...
|
|
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
|
|
Value *Op0LHS = Op0I->getOperand(0);
|
|
Value *Op0RHS = Op0I->getOperand(1);
|
|
switch (Op0I->getOpcode()) {
|
|
default: break;
|
|
case Instruction::Xor:
|
|
case Instruction::Or: {
|
|
// If the mask is only needed on one incoming arm, push it up.
|
|
if (!Op0I->hasOneUse()) break;
|
|
|
|
APInt NotAndRHS(~AndRHSMask);
|
|
if (MaskedValueIsZero(Op0LHS, NotAndRHS, 0, &I)) {
|
|
// Not masking anything out for the LHS, move to RHS.
|
|
Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS,
|
|
Op0RHS->getName()+".masked");
|
|
return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS);
|
|
}
|
|
if (!isa<Constant>(Op0RHS) &&
|
|
MaskedValueIsZero(Op0RHS, NotAndRHS, 0, &I)) {
|
|
// Not masking anything out for the RHS, move to LHS.
|
|
Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS,
|
|
Op0LHS->getName()+".masked");
|
|
return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS);
|
|
}
|
|
|
|
break;
|
|
}
|
|
case Instruction::Sub:
|
|
// -x & 1 -> x & 1
|
|
if (AndRHSMask == 1 && match(Op0LHS, m_Zero()))
|
|
return BinaryOperator::CreateAnd(Op0RHS, AndRHS);
|
|
|
|
break;
|
|
|
|
case Instruction::Shl:
|
|
case Instruction::LShr:
|
|
// (1 << x) & 1 --> zext(x == 0)
|
|
// (1 >> x) & 1 --> zext(x == 0)
|
|
if (AndRHSMask == 1 && Op0LHS == AndRHS) {
|
|
Value *NewICmp =
|
|
Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
|
|
return new ZExtInst(NewICmp, I.getType());
|
|
}
|
|
break;
|
|
}
|
|
|
|
// ((C1 OP zext(X)) & C2) -> zext((C1-X) & C2) if C2 fits in the bitwidth
|
|
// of X and OP behaves well when given trunc(C1) and X.
|
|
switch (Op0I->getOpcode()) {
|
|
default:
|
|
break;
|
|
case Instruction::Xor:
|
|
case Instruction::Or:
|
|
case Instruction::Mul:
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
Value *X;
|
|
ConstantInt *C1;
|
|
if (match(Op0I, m_c_BinOp(m_ZExt(m_Value(X)), m_ConstantInt(C1)))) {
|
|
if (AndRHSMask.isIntN(X->getType()->getScalarSizeInBits())) {
|
|
auto *TruncC1 = ConstantExpr::getTrunc(C1, X->getType());
|
|
Value *BinOp;
|
|
if (isa<ZExtInst>(Op0LHS))
|
|
BinOp = Builder->CreateBinOp(Op0I->getOpcode(), X, TruncC1);
|
|
else
|
|
BinOp = Builder->CreateBinOp(Op0I->getOpcode(), TruncC1, X);
|
|
auto *TruncC2 = ConstantExpr::getTrunc(AndRHS, X->getType());
|
|
auto *And = Builder->CreateAnd(BinOp, TruncC2);
|
|
return new ZExtInst(And, I.getType());
|
|
}
|
|
}
|
|
}
|
|
|
|
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
|
|
if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
|
|
return Res;
|
|
}
|
|
|
|
// If this is an integer truncation, and if the source is an 'and' with
|
|
// immediate, transform it. This frequently occurs for bitfield accesses.
|
|
{
|
|
Value *X = nullptr; ConstantInt *YC = nullptr;
|
|
if (match(Op0, m_Trunc(m_And(m_Value(X), m_ConstantInt(YC))))) {
|
|
// Change: and (trunc (and X, YC) to T), C2
|
|
// into : and (trunc X to T), trunc(YC) & C2
|
|
// This will fold the two constants together, which may allow
|
|
// other simplifications.
|
|
Value *NewCast = Builder->CreateTrunc(X, I.getType(), "and.shrunk");
|
|
Constant *C3 = ConstantExpr::getTrunc(YC, I.getType());
|
|
C3 = ConstantExpr::getAnd(C3, AndRHS);
|
|
return BinaryOperator::CreateAnd(NewCast, C3);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (isa<Constant>(Op1))
|
|
if (Instruction *FoldedLogic = foldOpWithConstantIntoOperand(I))
|
|
return FoldedLogic;
|
|
|
|
if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
|
|
return DeMorgan;
|
|
|
|
{
|
|
Value *A = nullptr, *B = nullptr, *C = nullptr;
|
|
// A&(A^B) => A & ~B
|
|
{
|
|
Value *tmpOp0 = Op0;
|
|
Value *tmpOp1 = Op1;
|
|
if (match(Op0, m_OneUse(m_Xor(m_Value(A), m_Value(B))))) {
|
|
if (A == Op1 || B == Op1 ) {
|
|
tmpOp1 = Op0;
|
|
tmpOp0 = Op1;
|
|
// Simplify below
|
|
}
|
|
}
|
|
|
|
if (match(tmpOp1, m_OneUse(m_Xor(m_Value(A), m_Value(B))))) {
|
|
if (B == tmpOp0) {
|
|
std::swap(A, B);
|
|
}
|
|
// Notice that the pattern (A&(~B)) is actually (A&(-1^B)), so if
|
|
// A is originally -1 (or a vector of -1 and undefs), then we enter
|
|
// an endless loop. By checking that A is non-constant we ensure that
|
|
// we will never get to the loop.
|
|
if (A == tmpOp0 && !isa<Constant>(A)) // A&(A^B) -> A & ~B
|
|
return BinaryOperator::CreateAnd(A, Builder->CreateNot(B));
|
|
}
|
|
}
|
|
|
|
// (A&((~A)|B)) -> A&B
|
|
if (match(Op0, m_c_Or(m_Not(m_Specific(Op1)), m_Value(A))))
|
|
return BinaryOperator::CreateAnd(A, Op1);
|
|
if (match(Op1, m_c_Or(m_Not(m_Specific(Op0)), m_Value(A))))
|
|
return BinaryOperator::CreateAnd(A, Op0);
|
|
|
|
// (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
|
|
if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
|
|
if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
|
|
return BinaryOperator::CreateAnd(Op0, Builder->CreateNot(C));
|
|
|
|
// ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
|
|
if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
|
|
if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
|
|
return BinaryOperator::CreateAnd(Op1, Builder->CreateNot(C));
|
|
|
|
// (A | B) & ((~A) ^ B) -> (A & B)
|
|
// (A | B) & (B ^ (~A)) -> (A & B)
|
|
// (B | A) & ((~A) ^ B) -> (A & B)
|
|
// (B | A) & (B ^ (~A)) -> (A & B)
|
|
if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
|
|
match(Op0, m_c_Or(m_Specific(A), m_Specific(B))))
|
|
return BinaryOperator::CreateAnd(A, B);
|
|
|
|
// ((~A) ^ B) & (A | B) -> (A & B)
|
|
// ((~A) ^ B) & (B | A) -> (A & B)
|
|
// (B ^ (~A)) & (A | B) -> (A & B)
|
|
// (B ^ (~A)) & (B | A) -> (A & B)
|
|
if (match(Op0, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
|
|
match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
|
|
return BinaryOperator::CreateAnd(A, B);
|
|
}
|
|
|
|
{
|
|
ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
|
|
ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
|
|
if (LHS && RHS)
|
|
if (Value *Res = FoldAndOfICmps(LHS, RHS))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
// TODO: Make this recursive; it's a little tricky because an arbitrary
|
|
// number of 'and' instructions might have to be created.
|
|
Value *X, *Y;
|
|
if (LHS && match(Op1, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = FoldAndOfICmps(LHS, Cmp))
|
|
return replaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = FoldAndOfICmps(LHS, Cmp))
|
|
return replaceInstUsesWith(I, Builder->CreateAnd(Res, X));
|
|
}
|
|
if (RHS && match(Op0, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = FoldAndOfICmps(Cmp, RHS))
|
|
return replaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = FoldAndOfICmps(Cmp, RHS))
|
|
return replaceInstUsesWith(I, Builder->CreateAnd(Res, X));
|
|
}
|
|
}
|
|
|
|
// If and'ing two fcmp, try combine them into one.
|
|
if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
|
|
if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
|
|
if (Value *Res = FoldAndOfFCmps(LHS, RHS))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
if (Instruction *CastedAnd = foldCastedBitwiseLogic(I))
|
|
return CastedAnd;
|
|
|
|
if (Instruction *Select = foldBoolSextMaskToSelect(I))
|
|
return Select;
|
|
|
|
return Changed ? &I : nullptr;
|
|
}
|
|
|
|
/// Given an OR instruction, check to see if this is a bswap idiom. If so,
|
|
/// insert the new intrinsic and return it.
|
|
Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
// Look through zero extends.
|
|
if (Instruction *Ext = dyn_cast<ZExtInst>(Op0))
|
|
Op0 = Ext->getOperand(0);
|
|
|
|
if (Instruction *Ext = dyn_cast<ZExtInst>(Op1))
|
|
Op1 = Ext->getOperand(0);
|
|
|
|
// (A | B) | C and A | (B | C) -> bswap if possible.
|
|
bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) ||
|
|
match(Op1, m_Or(m_Value(), m_Value()));
|
|
|
|
// (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
|
|
bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
|
|
match(Op1, m_LogicalShift(m_Value(), m_Value()));
|
|
|
|
// (A & B) | (C & D) -> bswap if possible.
|
|
bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) &&
|
|
match(Op1, m_And(m_Value(), m_Value()));
|
|
|
|
if (!OrOfOrs && !OrOfShifts && !OrOfAnds)
|
|
return nullptr;
|
|
|
|
SmallVector<Instruction*, 4> Insts;
|
|
if (!recognizeBSwapOrBitReverseIdiom(&I, true, false, Insts))
|
|
return nullptr;
|
|
Instruction *LastInst = Insts.pop_back_val();
|
|
LastInst->removeFromParent();
|
|
|
|
for (auto *Inst : Insts)
|
|
Worklist.Add(Inst);
|
|
return LastInst;
|
|
}
|
|
|
|
/// If all elements of two constant vectors are 0/-1 and inverses, return true.
|
|
static bool areInverseVectorBitmasks(Constant *C1, Constant *C2) {
|
|
unsigned NumElts = C1->getType()->getVectorNumElements();
|
|
for (unsigned i = 0; i != NumElts; ++i) {
|
|
Constant *EltC1 = C1->getAggregateElement(i);
|
|
Constant *EltC2 = C2->getAggregateElement(i);
|
|
if (!EltC1 || !EltC2)
|
|
return false;
|
|
|
|
// One element must be all ones, and the other must be all zeros.
|
|
// FIXME: Allow undef elements.
|
|
if (!((match(EltC1, m_Zero()) && match(EltC2, m_AllOnes())) ||
|
|
(match(EltC2, m_Zero()) && match(EltC1, m_AllOnes()))))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// We have an expression of the form (A & C) | (B & D). If A is a scalar or
|
|
/// vector composed of all-zeros or all-ones values and is the bitwise 'not' of
|
|
/// B, it can be used as the condition operand of a select instruction.
|
|
static Value *getSelectCondition(Value *A, Value *B,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
// If these are scalars or vectors of i1, A can be used directly.
|
|
Type *Ty = A->getType();
|
|
if (match(A, m_Not(m_Specific(B))) && Ty->getScalarType()->isIntegerTy(1))
|
|
return A;
|
|
|
|
// If A and B are sign-extended, look through the sexts to find the booleans.
|
|
Value *Cond;
|
|
if (match(A, m_SExt(m_Value(Cond))) &&
|
|
Cond->getType()->getScalarType()->isIntegerTy(1) &&
|
|
match(B, m_CombineOr(m_Not(m_SExt(m_Specific(Cond))),
|
|
m_SExt(m_Not(m_Specific(Cond))))))
|
|
return Cond;
|
|
|
|
// All scalar (and most vector) possibilities should be handled now.
|
|
// Try more matches that only apply to non-splat constant vectors.
|
|
if (!Ty->isVectorTy())
|
|
return nullptr;
|
|
|
|
// If both operands are constants, see if the constants are inverse bitmasks.
|
|
Constant *AC, *BC;
|
|
if (match(A, m_Constant(AC)) && match(B, m_Constant(BC)) &&
|
|
areInverseVectorBitmasks(AC, BC))
|
|
return ConstantExpr::getTrunc(AC, CmpInst::makeCmpResultType(Ty));
|
|
|
|
// If both operands are xor'd with constants using the same sexted boolean
|
|
// operand, see if the constants are inverse bitmasks.
|
|
if (match(A, (m_Xor(m_SExt(m_Value(Cond)), m_Constant(AC)))) &&
|
|
match(B, (m_Xor(m_SExt(m_Specific(Cond)), m_Constant(BC)))) &&
|
|
Cond->getType()->getScalarType()->isIntegerTy(1) &&
|
|
areInverseVectorBitmasks(AC, BC)) {
|
|
AC = ConstantExpr::getTrunc(AC, CmpInst::makeCmpResultType(Ty));
|
|
return Builder.CreateXor(Cond, AC);
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
/// We have an expression of the form (A & C) | (B & D). Try to simplify this
|
|
/// to "A' ? C : D", where A' is a boolean or vector of booleans.
|
|
static Value *matchSelectFromAndOr(Value *A, Value *C, Value *B, Value *D,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
// The potential condition of the select may be bitcasted. In that case, look
|
|
// through its bitcast and the corresponding bitcast of the 'not' condition.
|
|
Type *OrigType = A->getType();
|
|
Value *SrcA, *SrcB;
|
|
if (match(A, m_OneUse(m_BitCast(m_Value(SrcA)))) &&
|
|
match(B, m_OneUse(m_BitCast(m_Value(SrcB))))) {
|
|
A = SrcA;
|
|
B = SrcB;
|
|
}
|
|
|
|
if (Value *Cond = getSelectCondition(A, B, Builder)) {
|
|
// ((bc Cond) & C) | ((bc ~Cond) & D) --> bc (select Cond, (bc C), (bc D))
|
|
// The bitcasts will either all exist or all not exist. The builder will
|
|
// not create unnecessary casts if the types already match.
|
|
Value *BitcastC = Builder.CreateBitCast(C, A->getType());
|
|
Value *BitcastD = Builder.CreateBitCast(D, A->getType());
|
|
Value *Select = Builder.CreateSelect(Cond, BitcastC, BitcastD);
|
|
return Builder.CreateBitCast(Select, OrigType);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Fold (icmp)|(icmp) if possible.
|
|
Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
|
|
Instruction *CxtI) {
|
|
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
|
|
|
|
// Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
|
|
// if K1 and K2 are a one-bit mask.
|
|
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
|
|
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
|
|
|
|
if (LHS->getPredicate() == ICmpInst::ICMP_EQ && LHSC && LHSC->isZero() &&
|
|
RHS->getPredicate() == ICmpInst::ICMP_EQ && RHSC && RHSC->isZero()) {
|
|
|
|
BinaryOperator *LAnd = dyn_cast<BinaryOperator>(LHS->getOperand(0));
|
|
BinaryOperator *RAnd = dyn_cast<BinaryOperator>(RHS->getOperand(0));
|
|
if (LAnd && RAnd && LAnd->hasOneUse() && RHS->hasOneUse() &&
|
|
LAnd->getOpcode() == Instruction::And &&
|
|
RAnd->getOpcode() == Instruction::And) {
|
|
|
|
Value *Mask = nullptr;
|
|
Value *Masked = nullptr;
|
|
if (LAnd->getOperand(0) == RAnd->getOperand(0) &&
|
|
isKnownToBeAPowerOfTwo(LAnd->getOperand(1), DL, false, 0, &AC, CxtI,
|
|
&DT) &&
|
|
isKnownToBeAPowerOfTwo(RAnd->getOperand(1), DL, false, 0, &AC, CxtI,
|
|
&DT)) {
|
|
Mask = Builder->CreateOr(LAnd->getOperand(1), RAnd->getOperand(1));
|
|
Masked = Builder->CreateAnd(LAnd->getOperand(0), Mask);
|
|
} else if (LAnd->getOperand(1) == RAnd->getOperand(1) &&
|
|
isKnownToBeAPowerOfTwo(LAnd->getOperand(0), DL, false, 0, &AC,
|
|
CxtI, &DT) &&
|
|
isKnownToBeAPowerOfTwo(RAnd->getOperand(0), DL, false, 0, &AC,
|
|
CxtI, &DT)) {
|
|
Mask = Builder->CreateOr(LAnd->getOperand(0), RAnd->getOperand(0));
|
|
Masked = Builder->CreateAnd(LAnd->getOperand(1), Mask);
|
|
}
|
|
|
|
if (Masked)
|
|
return Builder->CreateICmp(ICmpInst::ICMP_NE, Masked, Mask);
|
|
}
|
|
}
|
|
|
|
// Fold (icmp ult/ule (A + C1), C3) | (icmp ult/ule (A + C2), C3)
|
|
// --> (icmp ult/ule ((A & ~(C1 ^ C2)) + max(C1, C2)), C3)
|
|
// The original condition actually refers to the following two ranges:
|
|
// [MAX_UINT-C1+1, MAX_UINT-C1+1+C3] and [MAX_UINT-C2+1, MAX_UINT-C2+1+C3]
|
|
// We can fold these two ranges if:
|
|
// 1) C1 and C2 is unsigned greater than C3.
|
|
// 2) The two ranges are separated.
|
|
// 3) C1 ^ C2 is one-bit mask.
|
|
// 4) LowRange1 ^ LowRange2 and HighRange1 ^ HighRange2 are one-bit mask.
|
|
// This implies all values in the two ranges differ by exactly one bit.
|
|
|
|
if ((PredL == ICmpInst::ICMP_ULT || PredL == ICmpInst::ICMP_ULE) &&
|
|
PredL == PredR && LHSC && RHSC && LHS->hasOneUse() && RHS->hasOneUse() &&
|
|
LHSC->getType() == RHSC->getType() &&
|
|
LHSC->getValue() == (RHSC->getValue())) {
|
|
|
|
Value *LAdd = LHS->getOperand(0);
|
|
Value *RAdd = RHS->getOperand(0);
|
|
|
|
Value *LAddOpnd, *RAddOpnd;
|
|
ConstantInt *LAddC, *RAddC;
|
|
if (match(LAdd, m_Add(m_Value(LAddOpnd), m_ConstantInt(LAddC))) &&
|
|
match(RAdd, m_Add(m_Value(RAddOpnd), m_ConstantInt(RAddC))) &&
|
|
LAddC->getValue().ugt(LHSC->getValue()) &&
|
|
RAddC->getValue().ugt(LHSC->getValue())) {
|
|
|
|
APInt DiffC = LAddC->getValue() ^ RAddC->getValue();
|
|
if (LAddOpnd == RAddOpnd && DiffC.isPowerOf2()) {
|
|
ConstantInt *MaxAddC = nullptr;
|
|
if (LAddC->getValue().ult(RAddC->getValue()))
|
|
MaxAddC = RAddC;
|
|
else
|
|
MaxAddC = LAddC;
|
|
|
|
APInt RRangeLow = -RAddC->getValue();
|
|
APInt RRangeHigh = RRangeLow + LHSC->getValue();
|
|
APInt LRangeLow = -LAddC->getValue();
|
|
APInt LRangeHigh = LRangeLow + LHSC->getValue();
|
|
APInt LowRangeDiff = RRangeLow ^ LRangeLow;
|
|
APInt HighRangeDiff = RRangeHigh ^ LRangeHigh;
|
|
APInt RangeDiff = LRangeLow.sgt(RRangeLow) ? LRangeLow - RRangeLow
|
|
: RRangeLow - LRangeLow;
|
|
|
|
if (LowRangeDiff.isPowerOf2() && LowRangeDiff == HighRangeDiff &&
|
|
RangeDiff.ugt(LHSC->getValue())) {
|
|
Value *MaskC = ConstantInt::get(LAddC->getType(), ~DiffC);
|
|
|
|
Value *NewAnd = Builder->CreateAnd(LAddOpnd, MaskC);
|
|
Value *NewAdd = Builder->CreateAdd(NewAnd, MaxAddC);
|
|
return (Builder->CreateICmp(LHS->getPredicate(), NewAdd, LHSC));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
|
|
if (PredicatesFoldable(PredL, PredR)) {
|
|
if (LHS->getOperand(0) == RHS->getOperand(1) &&
|
|
LHS->getOperand(1) == RHS->getOperand(0))
|
|
LHS->swapOperands();
|
|
if (LHS->getOperand(0) == RHS->getOperand(0) &&
|
|
LHS->getOperand(1) == RHS->getOperand(1)) {
|
|
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
|
|
unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
|
|
bool isSigned = LHS->isSigned() || RHS->isSigned();
|
|
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
|
|
}
|
|
}
|
|
|
|
// handle (roughly):
|
|
// (icmp ne (A & B), C) | (icmp ne (A & D), E)
|
|
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, false, Builder))
|
|
return V;
|
|
|
|
Value *LHS0 = LHS->getOperand(0), *RHS0 = RHS->getOperand(0);
|
|
if (LHS->hasOneUse() || RHS->hasOneUse()) {
|
|
// (icmp eq B, 0) | (icmp ult A, B) -> (icmp ule A, B-1)
|
|
// (icmp eq B, 0) | (icmp ugt B, A) -> (icmp ule A, B-1)
|
|
Value *A = nullptr, *B = nullptr;
|
|
if (PredL == ICmpInst::ICMP_EQ && LHSC && LHSC->isZero()) {
|
|
B = LHS0;
|
|
if (PredR == ICmpInst::ICMP_ULT && LHS0 == RHS->getOperand(1))
|
|
A = RHS0;
|
|
else if (PredR == ICmpInst::ICMP_UGT && LHS0 == RHS0)
|
|
A = RHS->getOperand(1);
|
|
}
|
|
// (icmp ult A, B) | (icmp eq B, 0) -> (icmp ule A, B-1)
|
|
// (icmp ugt B, A) | (icmp eq B, 0) -> (icmp ule A, B-1)
|
|
else if (PredR == ICmpInst::ICMP_EQ && RHSC && RHSC->isZero()) {
|
|
B = RHS0;
|
|
if (PredL == ICmpInst::ICMP_ULT && RHS0 == LHS->getOperand(1))
|
|
A = LHS0;
|
|
else if (PredL == ICmpInst::ICMP_UGT && LHS0 == RHS0)
|
|
A = LHS->getOperand(1);
|
|
}
|
|
if (A && B)
|
|
return Builder->CreateICmp(
|
|
ICmpInst::ICMP_UGE,
|
|
Builder->CreateAdd(B, ConstantInt::getSigned(B->getType(), -1)), A);
|
|
}
|
|
|
|
// E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
|
|
if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/true))
|
|
return V;
|
|
|
|
// E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n
|
|
if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/true))
|
|
return V;
|
|
|
|
if (Value *V = foldAndOrOfEqualityCmpsWithConstants(LHS, RHS, false, Builder))
|
|
return V;
|
|
|
|
// This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
|
|
if (!LHSC || !RHSC)
|
|
return nullptr;
|
|
|
|
if (LHSC == RHSC && PredL == PredR) {
|
|
// (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
|
|
if (PredL == ICmpInst::ICMP_NE && LHSC->isZero()) {
|
|
Value *NewOr = Builder->CreateOr(LHS0, RHS0);
|
|
return Builder->CreateICmp(PredL, NewOr, LHSC);
|
|
}
|
|
}
|
|
|
|
// (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
|
|
// iff C2 + CA == C1.
|
|
if (PredL == ICmpInst::ICMP_ULT && PredR == ICmpInst::ICMP_EQ) {
|
|
ConstantInt *AddC;
|
|
if (match(LHS0, m_Add(m_Specific(RHS0), m_ConstantInt(AddC))))
|
|
if (RHSC->getValue() + AddC->getValue() == LHSC->getValue())
|
|
return Builder->CreateICmpULE(LHS0, LHSC);
|
|
}
|
|
|
|
// From here on, we only handle:
|
|
// (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
|
|
if (LHS0 != RHS0)
|
|
return nullptr;
|
|
|
|
// ICMP_[US][GL]E X, C is folded to ICMP_[US][GL]T elsewhere.
|
|
if (PredL == ICmpInst::ICMP_UGE || PredL == ICmpInst::ICMP_ULE ||
|
|
PredR == ICmpInst::ICMP_UGE || PredR == ICmpInst::ICMP_ULE ||
|
|
PredL == ICmpInst::ICMP_SGE || PredL == ICmpInst::ICMP_SLE ||
|
|
PredR == ICmpInst::ICMP_SGE || PredR == ICmpInst::ICMP_SLE)
|
|
return nullptr;
|
|
|
|
// We can't fold (ugt x, C) | (sgt x, C2).
|
|
if (!PredicatesFoldable(PredL, PredR))
|
|
return nullptr;
|
|
|
|
// Ensure that the larger constant is on the RHS.
|
|
bool ShouldSwap;
|
|
if (CmpInst::isSigned(PredL) ||
|
|
(ICmpInst::isEquality(PredL) && CmpInst::isSigned(PredR)))
|
|
ShouldSwap = LHSC->getValue().sgt(RHSC->getValue());
|
|
else
|
|
ShouldSwap = LHSC->getValue().ugt(RHSC->getValue());
|
|
|
|
if (ShouldSwap) {
|
|
std::swap(LHS, RHS);
|
|
std::swap(LHSC, RHSC);
|
|
std::swap(PredL, PredR);
|
|
}
|
|
|
|
// At this point, we know we have two icmp instructions
|
|
// comparing a value against two constants and or'ing the result
|
|
// together. Because of the above check, we know that we only have
|
|
// ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
|
|
// icmp folding check above), that the two constants are not
|
|
// equal.
|
|
assert(LHSC != RHSC && "Compares not folded above?");
|
|
|
|
switch (PredL) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ:
|
|
// Potential folds for this case should already be handled.
|
|
break;
|
|
case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
|
|
case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
|
|
break;
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_ULT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
|
|
break;
|
|
case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
|
|
assert(!RHSC->isMaxValue(false) && "Missed icmp simplification");
|
|
return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue() + 1,
|
|
false, false);
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_SLT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
|
|
break;
|
|
case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
|
|
assert(!RHSC->isMaxValue(true) && "Missed icmp simplification");
|
|
return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue() + 1, true,
|
|
false);
|
|
}
|
|
break;
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
/// Optimize (fcmp)|(fcmp). NOTE: Unlike the rest of instcombine, this returns
|
|
/// a Value which should already be inserted into the function.
|
|
Value *InstCombiner::FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
|
|
Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
|
|
Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
|
|
FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
|
|
|
|
if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
|
|
// Swap RHS operands to match LHS.
|
|
Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
|
|
std::swap(Op1LHS, Op1RHS);
|
|
}
|
|
|
|
// Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
|
|
// This is a similar transformation to the one in FoldAndOfFCmps.
|
|
//
|
|
// Since (R & CC0) and (R & CC1) are either R or 0, we actually have this:
|
|
// bool(R & CC0) || bool(R & CC1)
|
|
// = bool((R & CC0) | (R & CC1))
|
|
// = bool(R & (CC0 | CC1)) <= by reversed distribution (contribution? ;)
|
|
if (Op0LHS == Op1LHS && Op0RHS == Op1RHS)
|
|
return getFCmpValue(getFCmpCode(Op0CC) | getFCmpCode(Op1CC), Op0LHS, Op0RHS,
|
|
Builder);
|
|
|
|
if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
|
|
RHS->getPredicate() == FCmpInst::FCMP_UNO &&
|
|
LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
|
|
if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
|
|
if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
|
|
// If either of the constants are nans, then the whole thing returns
|
|
// true.
|
|
if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
|
|
return Builder->getTrue();
|
|
|
|
// Otherwise, no need to compare the two constants, compare the
|
|
// rest.
|
|
return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
|
|
}
|
|
|
|
// Handle vector zeros. This occurs because the canonical form of
|
|
// "fcmp uno x,x" is "fcmp uno x, 0".
|
|
if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
|
|
isa<ConstantAggregateZero>(RHS->getOperand(1)))
|
|
return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// This helper function folds:
|
|
///
|
|
/// ((A | B) & C1) | (B & C2)
|
|
///
|
|
/// into:
|
|
///
|
|
/// (A & C1) | B
|
|
///
|
|
/// when the XOR of the two constants is "all ones" (-1).
|
|
Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op,
|
|
Value *A, Value *B, Value *C) {
|
|
ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
|
|
if (!CI1) return nullptr;
|
|
|
|
Value *V1 = nullptr;
|
|
ConstantInt *CI2 = nullptr;
|
|
if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return nullptr;
|
|
|
|
APInt Xor = CI1->getValue() ^ CI2->getValue();
|
|
if (!Xor.isAllOnesValue()) return nullptr;
|
|
|
|
if (V1 == A || V1 == B) {
|
|
Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1);
|
|
return BinaryOperator::CreateOr(NewOp, V1);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// \brief This helper function folds:
|
|
///
|
|
/// ((A | B) & C1) ^ (B & C2)
|
|
///
|
|
/// into:
|
|
///
|
|
/// (A & C1) ^ B
|
|
///
|
|
/// when the XOR of the two constants is "all ones" (-1).
|
|
Instruction *InstCombiner::FoldXorWithConstants(BinaryOperator &I, Value *Op,
|
|
Value *A, Value *B, Value *C) {
|
|
ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
|
|
if (!CI1)
|
|
return nullptr;
|
|
|
|
Value *V1 = nullptr;
|
|
ConstantInt *CI2 = nullptr;
|
|
if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2))))
|
|
return nullptr;
|
|
|
|
APInt Xor = CI1->getValue() ^ CI2->getValue();
|
|
if (!Xor.isAllOnesValue())
|
|
return nullptr;
|
|
|
|
if (V1 == A || V1 == B) {
|
|
Value *NewOp = Builder->CreateAnd(V1 == A ? B : A, CI1);
|
|
return BinaryOperator::CreateXor(NewOp, V1);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
|
|
// here. We should standardize that construct where it is needed or choose some
|
|
// other way to ensure that commutated variants of patterns are not missed.
|
|
Instruction *InstCombiner::visitOr(BinaryOperator &I) {
|
|
bool Changed = SimplifyAssociativeOrCommutative(I);
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifyVectorOp(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyOrInst(Op0, Op1, SQ))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
// See if we can simplify any instructions used by the instruction whose sole
|
|
// purpose is to compute bits we don't care about.
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
return &I;
|
|
|
|
// Do this before using distributive laws to catch simple and/or/not patterns.
|
|
if (Instruction *Xor = foldOrToXor(I, *Builder))
|
|
return Xor;
|
|
|
|
// (A&B)|(A&C) -> A&(B|C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyBSwap(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
|
|
ConstantInt *C1 = nullptr; Value *X = nullptr;
|
|
// (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
|
|
if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) &&
|
|
Op0->hasOneUse()) {
|
|
Value *Or = Builder->CreateOr(X, RHS);
|
|
Or->takeName(Op0);
|
|
return BinaryOperator::CreateXor(Or,
|
|
Builder->getInt(C1->getValue() & ~RHS->getValue()));
|
|
}
|
|
}
|
|
|
|
if (isa<Constant>(Op1))
|
|
if (Instruction *FoldedLogic = foldOpWithConstantIntoOperand(I))
|
|
return FoldedLogic;
|
|
|
|
// Given an OR instruction, check to see if this is a bswap.
|
|
if (Instruction *BSwap = MatchBSwap(I))
|
|
return BSwap;
|
|
|
|
{
|
|
Value *A;
|
|
const APInt *C;
|
|
// (X^C)|Y -> (X|Y)^C iff Y&C == 0
|
|
if (match(Op0, m_OneUse(m_Xor(m_Value(A), m_APInt(C)))) &&
|
|
MaskedValueIsZero(Op1, *C, 0, &I)) {
|
|
Value *NOr = Builder->CreateOr(A, Op1);
|
|
NOr->takeName(Op0);
|
|
return BinaryOperator::CreateXor(NOr,
|
|
ConstantInt::get(NOr->getType(), *C));
|
|
}
|
|
|
|
// Y|(X^C) -> (X|Y)^C iff Y&C == 0
|
|
if (match(Op1, m_OneUse(m_Xor(m_Value(A), m_APInt(C)))) &&
|
|
MaskedValueIsZero(Op0, *C, 0, &I)) {
|
|
Value *NOr = Builder->CreateOr(A, Op0);
|
|
NOr->takeName(Op0);
|
|
return BinaryOperator::CreateXor(NOr,
|
|
ConstantInt::get(NOr->getType(), *C));
|
|
}
|
|
}
|
|
|
|
Value *A, *B;
|
|
|
|
// ((~A & B) | A) -> (A | B)
|
|
if (match(Op0, m_c_And(m_Not(m_Specific(Op1)), m_Value(A))))
|
|
return BinaryOperator::CreateOr(A, Op1);
|
|
if (match(Op1, m_c_And(m_Not(m_Specific(Op0)), m_Value(A))))
|
|
return BinaryOperator::CreateOr(Op0, A);
|
|
|
|
// ((A & B) | ~A) -> (~A | B)
|
|
// The NOT is guaranteed to be in the RHS by complexity ordering.
|
|
if (match(Op1, m_Not(m_Value(A))) &&
|
|
match(Op0, m_c_And(m_Specific(A), m_Value(B))))
|
|
return BinaryOperator::CreateOr(Op1, B);
|
|
|
|
// (A & C)|(B & D)
|
|
Value *C = nullptr, *D = nullptr;
|
|
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
|
|
match(Op1, m_And(m_Value(B), m_Value(D)))) {
|
|
Value *V1 = nullptr, *V2 = nullptr;
|
|
ConstantInt *C1 = dyn_cast<ConstantInt>(C);
|
|
ConstantInt *C2 = dyn_cast<ConstantInt>(D);
|
|
if (C1 && C2) { // (A & C1)|(B & C2)
|
|
if ((C1->getValue() & C2->getValue()) == 0) {
|
|
// ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
|
|
// iff (C1&C2) == 0 and (N&~C1) == 0
|
|
if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
|
|
((V1 == B &&
|
|
MaskedValueIsZero(V2, ~C1->getValue(), 0, &I)) || // (V|N)
|
|
(V2 == B &&
|
|
MaskedValueIsZero(V1, ~C1->getValue(), 0, &I)))) // (N|V)
|
|
return BinaryOperator::CreateAnd(A,
|
|
Builder->getInt(C1->getValue()|C2->getValue()));
|
|
// Or commutes, try both ways.
|
|
if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
|
|
((V1 == A &&
|
|
MaskedValueIsZero(V2, ~C2->getValue(), 0, &I)) || // (V|N)
|
|
(V2 == A &&
|
|
MaskedValueIsZero(V1, ~C2->getValue(), 0, &I)))) // (N|V)
|
|
return BinaryOperator::CreateAnd(B,
|
|
Builder->getInt(C1->getValue()|C2->getValue()));
|
|
|
|
// ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2)
|
|
// iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
|
|
ConstantInt *C3 = nullptr, *C4 = nullptr;
|
|
if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
|
|
(C3->getValue() & ~C1->getValue()) == 0 &&
|
|
match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
|
|
(C4->getValue() & ~C2->getValue()) == 0) {
|
|
V2 = Builder->CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
|
|
return BinaryOperator::CreateAnd(V2,
|
|
Builder->getInt(C1->getValue()|C2->getValue()));
|
|
}
|
|
}
|
|
}
|
|
|
|
// Don't try to form a select if it's unlikely that we'll get rid of at
|
|
// least one of the operands. A select is generally more expensive than the
|
|
// 'or' that it is replacing.
|
|
if (Op0->hasOneUse() || Op1->hasOneUse()) {
|
|
// (Cond & C) | (~Cond & D) -> Cond ? C : D, and commuted variants.
|
|
if (Value *V = matchSelectFromAndOr(A, C, B, D, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(A, C, D, B, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(C, A, B, D, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(C, A, D, B, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(B, D, A, C, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(B, D, C, A, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(D, B, A, C, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
if (Value *V = matchSelectFromAndOr(D, B, C, A, *Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
}
|
|
|
|
// ((A|B)&1)|(B&-2) -> (A&1) | B
|
|
if (match(A, m_Or(m_Value(V1), m_Specific(B))) ||
|
|
match(A, m_Or(m_Specific(B), m_Value(V1)))) {
|
|
Instruction *Ret = FoldOrWithConstants(I, Op1, V1, B, C);
|
|
if (Ret) return Ret;
|
|
}
|
|
// (B&-2)|((A|B)&1) -> (A&1) | B
|
|
if (match(B, m_Or(m_Specific(A), m_Value(V1))) ||
|
|
match(B, m_Or(m_Value(V1), m_Specific(A)))) {
|
|
Instruction *Ret = FoldOrWithConstants(I, Op0, A, V1, D);
|
|
if (Ret) return Ret;
|
|
}
|
|
// ((A^B)&1)|(B&-2) -> (A&1) ^ B
|
|
if (match(A, m_Xor(m_Value(V1), m_Specific(B))) ||
|
|
match(A, m_Xor(m_Specific(B), m_Value(V1)))) {
|
|
Instruction *Ret = FoldXorWithConstants(I, Op1, V1, B, C);
|
|
if (Ret) return Ret;
|
|
}
|
|
// (B&-2)|((A^B)&1) -> (A&1) ^ B
|
|
if (match(B, m_Xor(m_Specific(A), m_Value(V1))) ||
|
|
match(B, m_Xor(m_Value(V1), m_Specific(A)))) {
|
|
Instruction *Ret = FoldXorWithConstants(I, Op0, A, V1, D);
|
|
if (Ret) return Ret;
|
|
}
|
|
}
|
|
|
|
// (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
|
|
if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
|
|
if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
|
|
return BinaryOperator::CreateOr(Op0, C);
|
|
|
|
// ((A ^ C) ^ B) | (B ^ A) -> (B ^ A) | C
|
|
if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
|
|
if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
|
|
return BinaryOperator::CreateOr(Op1, C);
|
|
|
|
// ((B | C) & A) | B -> B | (A & C)
|
|
if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A))))
|
|
return BinaryOperator::CreateOr(Op1, Builder->CreateAnd(A, C));
|
|
|
|
if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
|
|
return DeMorgan;
|
|
|
|
// Canonicalize xor to the RHS.
|
|
bool SwappedForXor = false;
|
|
if (match(Op0, m_Xor(m_Value(), m_Value()))) {
|
|
std::swap(Op0, Op1);
|
|
SwappedForXor = true;
|
|
}
|
|
|
|
// A | ( A ^ B) -> A | B
|
|
// A | (~A ^ B) -> A | ~B
|
|
// (A & B) | (A ^ B)
|
|
if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
|
|
if (Op0 == A || Op0 == B)
|
|
return BinaryOperator::CreateOr(A, B);
|
|
|
|
if (match(Op0, m_And(m_Specific(A), m_Specific(B))) ||
|
|
match(Op0, m_And(m_Specific(B), m_Specific(A))))
|
|
return BinaryOperator::CreateOr(A, B);
|
|
|
|
if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) {
|
|
Value *Not = Builder->CreateNot(B, B->getName()+".not");
|
|
return BinaryOperator::CreateOr(Not, Op0);
|
|
}
|
|
if (Op1->hasOneUse() && match(B, m_Not(m_Specific(Op0)))) {
|
|
Value *Not = Builder->CreateNot(A, A->getName()+".not");
|
|
return BinaryOperator::CreateOr(Not, Op0);
|
|
}
|
|
}
|
|
|
|
// A | ~(A | B) -> A | ~B
|
|
// A | ~(A ^ B) -> A | ~B
|
|
if (match(Op1, m_Not(m_Value(A))))
|
|
if (BinaryOperator *B = dyn_cast<BinaryOperator>(A))
|
|
if ((Op0 == B->getOperand(0) || Op0 == B->getOperand(1)) &&
|
|
Op1->hasOneUse() && (B->getOpcode() == Instruction::Or ||
|
|
B->getOpcode() == Instruction::Xor)) {
|
|
Value *NotOp = Op0 == B->getOperand(0) ? B->getOperand(1) :
|
|
B->getOperand(0);
|
|
Value *Not = Builder->CreateNot(NotOp, NotOp->getName()+".not");
|
|
return BinaryOperator::CreateOr(Not, Op0);
|
|
}
|
|
|
|
// (A & B) | (~A ^ B) -> (~A ^ B)
|
|
// (A & B) | (B ^ ~A) -> (~A ^ B)
|
|
// (B & A) | (~A ^ B) -> (~A ^ B)
|
|
// (B & A) | (B ^ ~A) -> (~A ^ B)
|
|
// The match order is important: match the xor first because the 'not'
|
|
// operation defines 'A'. We do not need to match the xor as Op0 because the
|
|
// xor was canonicalized to Op1 above.
|
|
if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
|
|
match(Op0, m_c_And(m_Specific(A), m_Specific(B))))
|
|
return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
|
|
|
|
if (SwappedForXor)
|
|
std::swap(Op0, Op1);
|
|
|
|
{
|
|
ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
|
|
ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
|
|
if (LHS && RHS)
|
|
if (Value *Res = FoldOrOfICmps(LHS, RHS, &I))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
// TODO: Make this recursive; it's a little tricky because an arbitrary
|
|
// number of 'or' instructions might have to be created.
|
|
Value *X, *Y;
|
|
if (LHS && match(Op1, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I))
|
|
return replaceInstUsesWith(I, Builder->CreateOr(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I))
|
|
return replaceInstUsesWith(I, Builder->CreateOr(Res, X));
|
|
}
|
|
if (RHS && match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I))
|
|
return replaceInstUsesWith(I, Builder->CreateOr(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I))
|
|
return replaceInstUsesWith(I, Builder->CreateOr(Res, X));
|
|
}
|
|
}
|
|
|
|
// (fcmp uno x, c) | (fcmp uno y, c) -> (fcmp uno x, y)
|
|
if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
|
|
if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
|
|
if (Value *Res = FoldOrOfFCmps(LHS, RHS))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
if (Instruction *CastedOr = foldCastedBitwiseLogic(I))
|
|
return CastedOr;
|
|
|
|
// or(sext(A), B) / or(B, sext(A)) --> A ? -1 : B, where A is i1 or <N x i1>.
|
|
if (match(Op0, m_OneUse(m_SExt(m_Value(A)))) &&
|
|
A->getType()->getScalarType()->isIntegerTy(1))
|
|
return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op1);
|
|
if (match(Op1, m_OneUse(m_SExt(m_Value(A)))) &&
|
|
A->getType()->getScalarType()->isIntegerTy(1))
|
|
return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op0);
|
|
|
|
// Note: If we've gotten to the point of visiting the outer OR, then the
|
|
// inner one couldn't be simplified. If it was a constant, then it won't
|
|
// be simplified by a later pass either, so we try swapping the inner/outer
|
|
// ORs in the hopes that we'll be able to simplify it this way.
|
|
// (X|C) | V --> (X|V) | C
|
|
ConstantInt *C1;
|
|
if (Op0->hasOneUse() && !isa<ConstantInt>(Op1) &&
|
|
match(Op0, m_Or(m_Value(A), m_ConstantInt(C1)))) {
|
|
Value *Inner = Builder->CreateOr(A, Op1);
|
|
Inner->takeName(Op0);
|
|
return BinaryOperator::CreateOr(Inner, C1);
|
|
}
|
|
|
|
// Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
|
|
// Since this OR statement hasn't been optimized further yet, we hope
|
|
// that this transformation will allow the new ORs to be optimized.
|
|
{
|
|
Value *X = nullptr, *Y = nullptr;
|
|
if (Op0->hasOneUse() && Op1->hasOneUse() &&
|
|
match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) {
|
|
Value *orTrue = Builder->CreateOr(A, C);
|
|
Value *orFalse = Builder->CreateOr(B, D);
|
|
return SelectInst::Create(X, orTrue, orFalse);
|
|
}
|
|
}
|
|
|
|
return Changed ? &I : nullptr;
|
|
}
|
|
|
|
/// A ^ B can be specified using other logic ops in a variety of patterns. We
|
|
/// can fold these early and efficiently by morphing an existing instruction.
|
|
static Instruction *foldXorToXor(BinaryOperator &I) {
|
|
assert(I.getOpcode() == Instruction::Xor);
|
|
Value *Op0 = I.getOperand(0);
|
|
Value *Op1 = I.getOperand(1);
|
|
Value *A, *B;
|
|
|
|
// There are 4 commuted variants for each of the basic patterns.
|
|
|
|
// (A & B) ^ (A | B) -> A ^ B
|
|
// (A & B) ^ (B | A) -> A ^ B
|
|
// (A | B) ^ (A & B) -> A ^ B
|
|
// (A | B) ^ (B & A) -> A ^ B
|
|
if ((match(Op0, m_And(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_c_Or(m_Specific(A), m_Specific(B)))) ||
|
|
(match(Op0, m_Or(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_c_And(m_Specific(A), m_Specific(B))))) {
|
|
I.setOperand(0, A);
|
|
I.setOperand(1, B);
|
|
return &I;
|
|
}
|
|
|
|
// (A | ~B) ^ (~A | B) -> A ^ B
|
|
// (~B | A) ^ (~A | B) -> A ^ B
|
|
// (~A | B) ^ (A | ~B) -> A ^ B
|
|
// (B | ~A) ^ (A | ~B) -> A ^ B
|
|
if ((match(Op0, m_c_Or(m_Value(A), m_Not(m_Value(B)))) &&
|
|
match(Op1, m_Or(m_Not(m_Specific(A)), m_Specific(B)))) ||
|
|
(match(Op0, m_c_Or(m_Not(m_Value(A)), m_Value(B))) &&
|
|
match(Op1, m_Or(m_Specific(A), m_Not(m_Specific(B)))))) {
|
|
I.setOperand(0, A);
|
|
I.setOperand(1, B);
|
|
return &I;
|
|
}
|
|
|
|
// (A & ~B) ^ (~A & B) -> A ^ B
|
|
// (~B & A) ^ (~A & B) -> A ^ B
|
|
// (~A & B) ^ (A & ~B) -> A ^ B
|
|
// (B & ~A) ^ (A & ~B) -> A ^ B
|
|
if ((match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
|
|
match(Op1, m_And(m_Not(m_Specific(A)), m_Specific(B)))) ||
|
|
(match(Op0, m_c_And(m_Not(m_Value(A)), m_Value(B))) &&
|
|
match(Op1, m_And(m_Specific(A), m_Not(m_Specific(B)))))) {
|
|
I.setOperand(0, A);
|
|
I.setOperand(1, B);
|
|
return &I;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
|
|
// here. We should standardize that construct where it is needed or choose some
|
|
// other way to ensure that commutated variants of patterns are not missed.
|
|
Instruction *InstCombiner::visitXor(BinaryOperator &I) {
|
|
bool Changed = SimplifyAssociativeOrCommutative(I);
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
if (Value *V = SimplifyVectorOp(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyXorInst(Op0, Op1, SQ))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Instruction *NewXor = foldXorToXor(I))
|
|
return NewXor;
|
|
|
|
// (A&B)^(A&C) -> A&(B^C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
// See if we can simplify any instructions used by the instruction whose sole
|
|
// purpose is to compute bits we don't care about.
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
return &I;
|
|
|
|
if (Value *V = SimplifyBSwap(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
// Apply DeMorgan's Law for 'nand' / 'nor' logic with an inverted operand.
|
|
Value *X, *Y;
|
|
|
|
// We must eliminate the and/or (one-use) for these transforms to not increase
|
|
// the instruction count.
|
|
// ~(~X & Y) --> (X | ~Y)
|
|
// ~(Y & ~X) --> (X | ~Y)
|
|
if (match(&I, m_Not(m_OneUse(m_c_And(m_Not(m_Value(X)), m_Value(Y)))))) {
|
|
Value *NotY = Builder->CreateNot(Y, Y->getName() + ".not");
|
|
return BinaryOperator::CreateOr(X, NotY);
|
|
}
|
|
// ~(~X | Y) --> (X & ~Y)
|
|
// ~(Y | ~X) --> (X & ~Y)
|
|
if (match(&I, m_Not(m_OneUse(m_c_Or(m_Not(m_Value(X)), m_Value(Y)))))) {
|
|
Value *NotY = Builder->CreateNot(Y, Y->getName() + ".not");
|
|
return BinaryOperator::CreateAnd(X, NotY);
|
|
}
|
|
|
|
// Is this a 'not' (~) fed by a binary operator?
|
|
BinaryOperator *NotVal;
|
|
if (match(&I, m_Not(m_BinOp(NotVal)))) {
|
|
if (NotVal->getOpcode() == Instruction::And ||
|
|
NotVal->getOpcode() == Instruction::Or) {
|
|
// Apply DeMorgan's Law when inverts are free:
|
|
// ~(X & Y) --> (~X | ~Y)
|
|
// ~(X | Y) --> (~X & ~Y)
|
|
if (IsFreeToInvert(NotVal->getOperand(0),
|
|
NotVal->getOperand(0)->hasOneUse()) &&
|
|
IsFreeToInvert(NotVal->getOperand(1),
|
|
NotVal->getOperand(1)->hasOneUse())) {
|
|
Value *NotX = Builder->CreateNot(NotVal->getOperand(0), "notlhs");
|
|
Value *NotY = Builder->CreateNot(NotVal->getOperand(1), "notrhs");
|
|
if (NotVal->getOpcode() == Instruction::And)
|
|
return BinaryOperator::CreateOr(NotX, NotY);
|
|
return BinaryOperator::CreateAnd(NotX, NotY);
|
|
}
|
|
}
|
|
|
|
// ~(~X >>s Y) --> (X >>s Y)
|
|
if (match(NotVal, m_AShr(m_Not(m_Value(X)), m_Value(Y))))
|
|
return BinaryOperator::CreateAShr(X, Y);
|
|
|
|
// If we are inverting a right-shifted constant, we may be able to eliminate
|
|
// the 'not' by inverting the constant and using the opposite shift type.
|
|
// Canonicalization rules ensure that only a negative constant uses 'ashr',
|
|
// but we must check that in case that transform has not fired yet.
|
|
const APInt *C;
|
|
if (match(NotVal, m_AShr(m_APInt(C), m_Value(Y))) && C->isNegative()) {
|
|
// ~(C >>s Y) --> ~C >>u Y (when inverting the replicated sign bits)
|
|
Constant *NotC = ConstantInt::get(I.getType(), ~(*C));
|
|
return BinaryOperator::CreateLShr(NotC, Y);
|
|
}
|
|
|
|
if (match(NotVal, m_LShr(m_APInt(C), m_Value(Y))) && C->isNonNegative()) {
|
|
// ~(C >>u Y) --> ~C >>s Y (when inverting the replicated sign bits)
|
|
Constant *NotC = ConstantInt::get(I.getType(), ~(*C));
|
|
return BinaryOperator::CreateAShr(NotC, Y);
|
|
}
|
|
}
|
|
|
|
// xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
|
|
ICmpInst::Predicate Pred;
|
|
if (match(Op0, m_OneUse(m_Cmp(Pred, m_Value(), m_Value()))) &&
|
|
match(Op1, m_AllOnes())) {
|
|
cast<CmpInst>(Op0)->setPredicate(CmpInst::getInversePredicate(Pred));
|
|
return replaceInstUsesWith(I, Op0);
|
|
}
|
|
|
|
if (ConstantInt *RHSC = dyn_cast<ConstantInt>(Op1)) {
|
|
// fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
|
|
if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
|
|
if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
|
|
if (CI->hasOneUse() && Op0C->hasOneUse()) {
|
|
Instruction::CastOps Opcode = Op0C->getOpcode();
|
|
if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) &&
|
|
(RHSC == ConstantExpr::getCast(Opcode, Builder->getTrue(),
|
|
Op0C->getDestTy()))) {
|
|
CI->setPredicate(CI->getInversePredicate());
|
|
return CastInst::Create(Opcode, CI, Op0C->getType());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
|
|
// ~(c-X) == X-c-1 == X+(-c-1)
|
|
if (Op0I->getOpcode() == Instruction::Sub && RHSC->isAllOnesValue())
|
|
if (Constant *Op0I0C = dyn_cast<Constant>(Op0I->getOperand(0))) {
|
|
Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C);
|
|
return BinaryOperator::CreateAdd(Op0I->getOperand(1),
|
|
SubOne(NegOp0I0C));
|
|
}
|
|
|
|
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
|
|
if (Op0I->getOpcode() == Instruction::Add) {
|
|
// ~(X-c) --> (-c-1)-X
|
|
if (RHSC->isAllOnesValue()) {
|
|
Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI);
|
|
return BinaryOperator::CreateSub(SubOne(NegOp0CI),
|
|
Op0I->getOperand(0));
|
|
} else if (RHSC->getValue().isSignMask()) {
|
|
// (X + C) ^ signmask -> (X + C + signmask)
|
|
Constant *C = Builder->getInt(RHSC->getValue() + Op0CI->getValue());
|
|
return BinaryOperator::CreateAdd(Op0I->getOperand(0), C);
|
|
|
|
}
|
|
} else if (Op0I->getOpcode() == Instruction::Or) {
|
|
// (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
|
|
if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue(),
|
|
0, &I)) {
|
|
Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHSC);
|
|
// Anything in both C1 and C2 is known to be zero, remove it from
|
|
// NewRHS.
|
|
Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHSC);
|
|
NewRHS = ConstantExpr::getAnd(NewRHS,
|
|
ConstantExpr::getNot(CommonBits));
|
|
Worklist.Add(Op0I);
|
|
I.setOperand(0, Op0I->getOperand(0));
|
|
I.setOperand(1, NewRHS);
|
|
return &I;
|
|
}
|
|
} else if (Op0I->getOpcode() == Instruction::LShr) {
|
|
// ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
|
|
// E1 = "X ^ C1"
|
|
BinaryOperator *E1;
|
|
ConstantInt *C1;
|
|
if (Op0I->hasOneUse() &&
|
|
(E1 = dyn_cast<BinaryOperator>(Op0I->getOperand(0))) &&
|
|
E1->getOpcode() == Instruction::Xor &&
|
|
(C1 = dyn_cast<ConstantInt>(E1->getOperand(1)))) {
|
|
// fold (C1 >> C2) ^ C3
|
|
ConstantInt *C2 = Op0CI, *C3 = RHSC;
|
|
APInt FoldConst = C1->getValue().lshr(C2->getValue());
|
|
FoldConst ^= C3->getValue();
|
|
// Prepare the two operands.
|
|
Value *Opnd0 = Builder->CreateLShr(E1->getOperand(0), C2);
|
|
Opnd0->takeName(Op0I);
|
|
cast<Instruction>(Opnd0)->setDebugLoc(I.getDebugLoc());
|
|
Value *FoldVal = ConstantInt::get(Opnd0->getType(), FoldConst);
|
|
|
|
return BinaryOperator::CreateXor(Opnd0, FoldVal);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (isa<Constant>(Op1))
|
|
if (Instruction *FoldedLogic = foldOpWithConstantIntoOperand(I))
|
|
return FoldedLogic;
|
|
|
|
{
|
|
Value *A, *B;
|
|
if (match(Op1, m_OneUse(m_Or(m_Value(A), m_Value(B))))) {
|
|
if (A == Op0) { // A^(A|B) == A^(B|A)
|
|
cast<BinaryOperator>(Op1)->swapOperands();
|
|
std::swap(A, B);
|
|
}
|
|
if (B == Op0) { // A^(B|A) == (B|A)^A
|
|
I.swapOperands(); // Simplified below.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
} else if (match(Op1, m_OneUse(m_And(m_Value(A), m_Value(B))))) {
|
|
if (A == Op0) { // A^(A&B) -> A^(B&A)
|
|
cast<BinaryOperator>(Op1)->swapOperands();
|
|
std::swap(A, B);
|
|
}
|
|
if (B == Op0) { // A^(B&A) -> (B&A)^A
|
|
I.swapOperands(); // Simplified below.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
}
|
|
}
|
|
|
|
{
|
|
Value *A, *B;
|
|
if (match(Op0, m_OneUse(m_Or(m_Value(A), m_Value(B))))) {
|
|
if (A == Op1) // (B|A)^B == (A|B)^B
|
|
std::swap(A, B);
|
|
if (B == Op1) // (A|B)^B == A & ~B
|
|
return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1));
|
|
} else if (match(Op0, m_OneUse(m_And(m_Value(A), m_Value(B))))) {
|
|
if (A == Op1) // (A&B)^A -> (B&A)^A
|
|
std::swap(A, B);
|
|
const APInt *C;
|
|
if (B == Op1 && // (B&A)^A == ~B & A
|
|
!match(Op1, m_APInt(C))) { // Canonical form is (B&C)^C
|
|
return BinaryOperator::CreateAnd(Builder->CreateNot(A), Op1);
|
|
}
|
|
}
|
|
}
|
|
|
|
{
|
|
Value *A, *B, *C, *D;
|
|
// (A ^ C)^(A | B) -> ((~A) & B) ^ C
|
|
if (match(Op0, m_Xor(m_Value(D), m_Value(C))) &&
|
|
match(Op1, m_Or(m_Value(A), m_Value(B)))) {
|
|
if (D == A)
|
|
return BinaryOperator::CreateXor(
|
|
Builder->CreateAnd(Builder->CreateNot(A), B), C);
|
|
if (D == B)
|
|
return BinaryOperator::CreateXor(
|
|
Builder->CreateAnd(Builder->CreateNot(B), A), C);
|
|
}
|
|
// (A | B)^(A ^ C) -> ((~A) & B) ^ C
|
|
if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_Xor(m_Value(D), m_Value(C)))) {
|
|
if (D == A)
|
|
return BinaryOperator::CreateXor(
|
|
Builder->CreateAnd(Builder->CreateNot(A), B), C);
|
|
if (D == B)
|
|
return BinaryOperator::CreateXor(
|
|
Builder->CreateAnd(Builder->CreateNot(B), A), C);
|
|
}
|
|
// (A & B) ^ (A ^ B) -> (A | B)
|
|
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_c_Xor(m_Specific(A), m_Specific(B))))
|
|
return BinaryOperator::CreateOr(A, B);
|
|
// (A ^ B) ^ (A & B) -> (A | B)
|
|
if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
|
|
match(Op1, m_c_And(m_Specific(A), m_Specific(B))))
|
|
return BinaryOperator::CreateOr(A, B);
|
|
}
|
|
|
|
// (A & ~B) ^ ~A -> ~(A & B)
|
|
// (~B & A) ^ ~A -> ~(A & B)
|
|
Value *A, *B;
|
|
if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
|
|
match(Op1, m_Not(m_Specific(A))))
|
|
return BinaryOperator::CreateNot(Builder->CreateAnd(A, B));
|
|
|
|
// (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
|
|
if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
|
|
if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
|
|
if (PredicatesFoldable(LHS->getPredicate(), RHS->getPredicate())) {
|
|
if (LHS->getOperand(0) == RHS->getOperand(1) &&
|
|
LHS->getOperand(1) == RHS->getOperand(0))
|
|
LHS->swapOperands();
|
|
if (LHS->getOperand(0) == RHS->getOperand(0) &&
|
|
LHS->getOperand(1) == RHS->getOperand(1)) {
|
|
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
|
|
unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
|
|
bool isSigned = LHS->isSigned() || RHS->isSigned();
|
|
return replaceInstUsesWith(I,
|
|
getNewICmpValue(isSigned, Code, Op0, Op1,
|
|
Builder));
|
|
}
|
|
}
|
|
|
|
if (Instruction *CastedXor = foldCastedBitwiseLogic(I))
|
|
return CastedXor;
|
|
|
|
return Changed ? &I : nullptr;
|
|
}
|