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| author | Nick Lewycky <nicholas@mxc.ca> | 2009-09-20 05:48:50 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2009-09-20 05:48:50 +0000 |
| commit | b4f150b44b10efd07b2a88484830602476bd8d7a (patch) | |
| tree | 08ace6b453257738cf3bdaffb9a73c3dee86a84c | |
| parent | a81653676cd5fc5e695af54399394225e8d89b79 (diff) | |
| download | external_llvm-b4f150b44b10efd07b2a88484830602476bd8d7a.zip external_llvm-b4f150b44b10efd07b2a88484830602476bd8d7a.tar.gz external_llvm-b4f150b44b10efd07b2a88484830602476bd8d7a.tar.bz2 | |
Try turning icmp(bitcast(x), bitcast(y)) into icmp(bitcast(bitcast(x)), y) in
the hopes that the two bitcasts will merge.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82371 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 10 | ||||
| -rw-r--r-- | test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll | 5 |
2 files changed, 15 insertions, 0 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index 8c65b56..3f5c7ef 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -1627,6 +1627,16 @@ Constant *llvm::ConstantFoldCompareInstruction(LLVMContext &Context, if (Result != -1) return ConstantInt::get(Type::getInt1Ty(Context), Result); + // If the right hand side is a bitcast, try using its inverse to simplify + // it by moving it to the left hand side. + if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) { + if (CE2->getOpcode() == Instruction::BitCast) { + Constant *CE2Op0 = CE2->getOperand(0); + Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType()); + return ConstantExpr::getICmp(pred, Inverse, CE2Op0); + } + } + if (!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) { // If C2 is a constant expr and C1 isn't, flip them around and fold the // other way if possible. diff --git a/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll b/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll index debf9a8..0a40c0c 100644 --- a/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll +++ b/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll @@ -23,3 +23,8 @@ global i1 srem (i1 icmp ult (i8* @X, i8* @Y), i1 icmp ult (i8* @X, i8* @Z)) global i1 urem (i1 icmp ult (i8* @X, i8* @Y), i1 icmp ult (i8* @X, i8* @Z)) ; CHECK-NOT: icmp ; CHECK: i1 false + +global i1 icmp ule (i32* bitcast (i8* @X to i32*), i32* bitcast (i8* @Y to i32*)) +; CHECK-NOT: bitcast +; CHECK: icmp + |