Revert "[InstSimplify] Add support for bitcasts"

This reverts commit r276698.  Clang has tests which rely on the
optimizer :(

llvm-svn: 276700

llvm/include/llvm/Analysis/InstructionSimplify.h

@@ -245,13 +245,6 @@ namespace llvm {
                            AssumptionCache *AC = nullptr,
                            const Instruction *CxtI = nullptr);
 
-  /// Given operands for an BitCastInst, fold the result or return null.
-  Value *SimplifyBitCastInst(Value *Op, Type *Ty, const DataLayout &DL,
-                             const TargetLibraryInfo *TLI = nullptr,
-                             const DominatorTree *DT = nullptr,
-                             AssumptionCache *AC = nullptr,
-                             const Instruction *CxtI = nullptr);
-
   //=== Helper functions for higher up the class hierarchy.
 
 

llvm/lib/Analysis/InstructionSimplify.cpp

@@ -70,7 +70,6 @@ static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
-static Value *SimplifyBitCastInst(Value *, Type *, const Query &, unsigned);
 
 /// For a boolean type, or a vector of boolean type, return false, or
 /// a vector with every element false, as appropriate for the type.
@@ -3811,30 +3810,6 @@ Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout &DL,
                              RecursionLimit);
 }
 
-static Value *SimplifyBitCastInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
-  if (auto *C = dyn_cast<Constant>(Op))
-    return ConstantFoldCastOperand(Instruction::BitCast, C, Ty, Q.DL);
-
-  // bitcast x -> x
-  if (Op->getType() == Ty)
-    return Op;
-
-  // bitcast(bitcast x) -> x
-  if (auto *BC = dyn_cast<BitCastInst>(Op))
-    if (BC->getOperand(0)->getType() == Ty)
-      return BC->getOperand(0);
-
-  return nullptr;
-}
-
-Value *llvm::SimplifyBitCastInst(Value *Op, Type *Ty, const DataLayout &DL,
-                               const TargetLibraryInfo *TLI,
-                               const DominatorTree *DT, AssumptionCache *AC,
-                               const Instruction *CxtI) {
-  return ::SimplifyBitCastInst(Op, Ty, Query(DL, TLI, DT, AC, CxtI),
-                               RecursionLimit);
-}
-
 //=== Helper functions for higher up the class hierarchy.
 
 /// Given operands for a BinaryOperator, see if we can fold the result.
@@ -4305,10 +4280,6 @@ Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout &DL,
     Result =
         SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT, AC, I);
     break;
-  case Instruction::BitCast:
-    Result =
-        SimplifyBitCastInst(I->getOperand(0), I->getType(), DL, TLI, DT, AC, I);
-    break;
   }
 
   // In general, it is possible for computeKnownBits to determine all bits in a

llvm/test/Transforms/GVN/pr14166.ll

@@ -18,7 +18,9 @@ define <2 x i32> @test1() {
 ; CHECK: %v4 = bitcast <2 x i32>* %v1 to <2 x i8*>*
 ; CHECK: store <2 x i8*> %v3, <2 x i8*>* %v4
 ; CHECK: %1 = ptrtoint <2 x i8*> %v3 to <2 x i32>
-; CHECK: ret <2 x i32> %1
+; CHECK: %2 = bitcast <2 x i32> %1 to i64
+; CHECK: %3 = bitcast i64 %2 to <2 x i32>
+; CHECK: ret <2 x i32> %3
 }
 
 declare void @anything(<2 x i32>*)

llvm/test/Transforms/InstSimplify/cast.ll

@@ -1,27 +0,0 @@
-; RUN: opt -S -instsimplify < %s | FileCheck %s
-
-define i1 @test1(i1 %V) {
-entry:
-  %Z = zext i1 %V to i32
-  %T = trunc i32 %Z to i1
-  ret i1 %T
-; CHECK-LABEL: define i1 @test1(
-; CHECK: ret i1 %V
-}
-
-define i8* @test2(i8* %V) {
-entry:
-  %BC1 = bitcast i8* %V to i32*
-  %BC2 = bitcast i32* %BC1 to i8*
-  ret i8* %BC2
-; CHECK-LABEL: define i8* @test2(
-; CHECK: ret i8* %V
-}
-
-define i8* @test3(i8* %V) {
-entry:
-  %BC = bitcast i8* %V to i8*
-  ret i8* %BC
-; CHECK-LABEL: define i8* @test3(
-; CHECK: ret i8* %V
-}