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Refactor code used in InstCombine::FoldAndOfICmps to new file. 

This will be used by SimplifyCfg in a later commit.

llvm-svn: 146803
This commit is contained in:
Pete Cooper 2011-12-17 01:20:32 +00:00
parent 3cac132d05
commit ebf98c1304
4 changed files with 175 additions and 72 deletions
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66
llvm/include/llvm/Transforms/Utils/CmpInstAnalysis.h Normal file
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@ -0,0 +1,66 @@
//===-- CmpInstAnalysis.h - Utils to help fold compare insts ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file holds routines to help analyse compare instructions
// and fold them into constants or other compare instructions
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_CMPINSTANALYSIS_H
#define LLVM_TRANSFORMS_UTILS_CMPINSTANALYSIS_H
#include "llvm/InstrTypes.h"
namespace llvm {
class ICmpInst;
class Value;
/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
/// are carefully arranged to allow folding of expressions such as:
///
/// (A < B) | (A > B) --> (A != B)
///
/// Note that this is only valid if the first and second predicates have the
/// same sign. Is illegal to do: (A u< B) | (A s> B)
///
/// Three bits are used to represent the condition, as follows:
/// 0 A > B
/// 1 A == B
/// 2 A < B
///
/// <=> Value Definition
/// 000 0 Always false
/// 001 1 A > B
/// 010 2 A == B
/// 011 3 A >= B
/// 100 4 A < B
/// 101 5 A != B
/// 110 6 A <= B
/// 111 7 Always true
///
unsigned getICmpCode(const ICmpInst *ICI, bool InvertPred = false);
/// getICmpValue - This is the complement of getICmpCode, which turns an
/// opcode and two operands into either a constant true or false, or the
/// predicate for a new ICmp instruction. The sign is passed in to determine
/// which kind of predicate to use in the new icmp instruction.
/// Non-NULL return value will be a true or false constant.
/// NULL return means a new ICmp is needed. The predicate for which is
/// output in NewICmpPred.
Value *getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
CmpInst::Predicate &NewICmpPred);
/// PredicatesFoldable - Return true if both predicates match sign or if at
/// least one of them is an equality comparison (which is signless).
bool PredicatesFoldable(CmpInst::Predicate p1, CmpInst::Predicate p2);
} // end namespace llvm
#endif

83
llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
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@ -14,6 +14,7 @@
#include "InstCombine.h"
#include "llvm/Intrinsics.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/PatternMatch.h"
using namespace llvm;
@ -62,50 +63,6 @@ static inline Value *dyn_castNotVal(Value *V) {
return 0;
}
/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
/// are carefully arranged to allow folding of expressions such as:
///
/// (A < B) | (A > B) --> (A != B)
///
/// Note that this is only valid if the first and second predicates have the
/// same sign. Is illegal to do: (A u< B) | (A s> B)
///
/// Three bits are used to represent the condition, as follows:
/// 0 A > B
/// 1 A == B
/// 2 A < B
///
/// <=> Value Definition
/// 000 0 Always false
/// 001 1 A > B
/// 010 2 A == B
/// 011 3 A >= B
/// 100 4 A < B
/// 101 5 A != B
/// 110 6 A <= B
/// 111 7 Always true
///
static unsigned getICmpCode(const ICmpInst *ICI) {
switch (ICI->getPredicate()) {
// False -> 0
case ICmpInst::ICMP_UGT: return 1; // 001
case ICmpInst::ICMP_SGT: return 1; // 001
case ICmpInst::ICMP_EQ: return 2; // 010
case ICmpInst::ICMP_UGE: return 3; // 011
case ICmpInst::ICMP_SGE: return 3; // 011
case ICmpInst::ICMP_ULT: return 4; // 100
case ICmpInst::ICMP_SLT: return 4; // 100
case ICmpInst::ICMP_NE: return 5; // 101
case ICmpInst::ICMP_ULE: return 6; // 110
case ICmpInst::ICMP_SLE: return 6; // 110
// True -> 7
default:
llvm_unreachable("Invalid ICmp predicate!");
return 0;
}
}
/// getFCmpCode - Similar to getICmpCode but for FCmpInst. This encodes a fcmp
/// predicate into a three bit mask. It also returns whether it is an ordered
/// predicate by reference.
@ -138,23 +95,12 @@ static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
/// opcode and two operands into either a constant true or false, or a brand
/// new ICmp instruction. The sign is passed in to determine which kind
/// of predicate to use in the new icmp instruction.
static Value *getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
InstCombiner::BuilderTy *Builder) {
CmpInst::Predicate Pred;
switch (Code) {
default: assert(0 && "Illegal ICmp code!");
case 0: // False.
return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
case 1: Pred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break;
case 2: Pred = ICmpInst::ICMP_EQ; break;
case 3: Pred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break;
case 4: Pred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break;
case 5: Pred = ICmpInst::ICMP_NE; break;
case 6: Pred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break;
case 7: // True.
return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
}
return Builder->CreateICmp(Pred, LHS, RHS);
Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
InstCombiner::BuilderTy *Builder) {
ICmpInst::Predicate NewPred;
if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
return NewConstant;
return Builder->CreateICmp(NewPred, LHS, RHS);
}
/// getFCmpValue - This is the complement of getFCmpCode, which turns an
@ -180,14 +126,6 @@ static Value *getFCmpValue(bool isordered, unsigned code,
return Builder->CreateFCmp(Pred, LHS, RHS);
}
/// PredicatesFoldable - Return true if both predicates match sign or if at
/// least one of them is an equality comparison (which is signless).
static bool PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
(CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
(CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
}
// OptAndOp - This handles expressions of the form ((val OP C1) & C2). Where
// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is
// guaranteed to be a binary operator.
@ -728,7 +666,7 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
bool isSigned = LHS->isSigned() || RHS->isSigned();
return getICmpValue(isSigned, Code, Op0, Op1, Builder);
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
}
}
@ -1469,7 +1407,7 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
bool isSigned = LHS->isSigned() || RHS->isSigned();
return getICmpValue(isSigned, Code, Op0, Op1, Builder);
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
}
}
@ -2281,7 +2219,8 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
bool isSigned = LHS->isSigned() || RHS->isSigned();
return ReplaceInstUsesWith(I,
getICmpValue(isSigned, Code, Op0, Op1, Builder));
getNewICmpValue(isSigned, Code, Op0, Op1,
Builder));
}
}

1
llvm/lib/Transforms/Utils/CMakeLists.txt
View File

@ -6,6 +6,7 @@ add_llvm_library(LLVMTransformUtils
BuildLibCalls.cpp
CloneFunction.cpp
CloneModule.cpp
CmpInstAnalysis.cpp
CodeExtractor.cpp
DemoteRegToStack.cpp
InlineFunction.cpp

97
llvm/lib/Transforms/Utils/CmpInstAnalysis.cpp Normal file
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@ -0,0 +1,97 @@
//===- CmpInstAnalysis.cpp - Utils to help fold compares ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file holds routines to help analyse compare instructions
// and fold them into constants or other compare instructions
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
using namespace llvm;
/// getICmpCode - Encode a icmp predicate into a three bit mask. These bits
/// are carefully arranged to allow folding of expressions such as:
///
/// (A < B) | (A > B) --> (A != B)
///
/// Note that this is only valid if the first and second predicates have the
/// same sign. Is illegal to do: (A u< B) | (A s> B)
///
/// Three bits are used to represent the condition, as follows:
/// 0 A > B
/// 1 A == B
/// 2 A < B
///
/// <=> Value Definition
/// 000 0 Always false
/// 001 1 A > B
/// 010 2 A == B
/// 011 3 A >= B
/// 100 4 A < B
/// 101 5 A != B
/// 110 6 A <= B
/// 111 7 Always true
///
unsigned llvm::getICmpCode(const ICmpInst *ICI, bool InvertPred) {
ICmpInst::Predicate Pred = InvertPred ? ICI->getInversePredicate()
: ICI->getPredicate();
switch (Pred) {
// False -> 0
case ICmpInst::ICMP_UGT: return 1; // 001
case ICmpInst::ICMP_SGT: return 1; // 001
case ICmpInst::ICMP_EQ: return 2; // 010
case ICmpInst::ICMP_UGE: return 3; // 011
case ICmpInst::ICMP_SGE: return 3; // 011
case ICmpInst::ICMP_ULT: return 4; // 100
case ICmpInst::ICMP_SLT: return 4; // 100
case ICmpInst::ICMP_NE: return 5; // 101
case ICmpInst::ICMP_ULE: return 6; // 110
case ICmpInst::ICMP_SLE: return 6; // 110
// True -> 7
default:
llvm_unreachable("Invalid ICmp predicate!");
return 0;
}
}
/// getICmpValue - This is the complement of getICmpCode, which turns an
/// opcode and two operands into either a constant true or false, or the
/// predicate for a new ICmp instruction. The sign is passed in to determine
/// which kind of predicate to use in the new icmp instruction.
/// Non-NULL return value will be a true or false constant.
/// NULL return means a new ICmp is needed. The predicate for which is
/// output in NewICmpPred.
Value *llvm::getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
CmpInst::Predicate &NewICmpPred) {
switch (Code) {
default: assert(0 && "Illegal ICmp code!");
case 0: // False.
return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
case 1: NewICmpPred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break;
case 2: NewICmpPred = ICmpInst::ICMP_EQ; break;
case 3: NewICmpPred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break;
case 4: NewICmpPred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break;
case 5: NewICmpPred = ICmpInst::ICMP_NE; break;
case 6: NewICmpPred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break;
case 7: // True.
return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
}
return NULL;
}
/// PredicatesFoldable - Return true if both predicates match sign or if at
/// least one of them is an equality comparison (which is signless).
bool llvm::PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
(CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
(CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
}