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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 | 4a0345207732c6de918e2a9fafe8326a2ffb2cb0 (patch) | |
| tree | b0e489dd7efe1946eae60e1dce1598f4e58ded25 | |
| parent | b1f2e101db658f93827a4e73c6d0ac3eed2d8f5a (diff) | |
| download | bcm5719-llvm-4a0345207732c6de918e2a9fafe8326a2ffb2cb0.tar.gz bcm5719-llvm-4a0345207732c6de918e2a9fafe8326a2ffb2cb0.zip | |
Try turning icmp(bitcast(x), bitcast(y)) into icmp(bitcast(bitcast(x)), y) in
the hopes that the two bitcasts will merge.
llvm-svn: 82371
| -rw-r--r-- | llvm/lib/VMCore/ConstantFold.cpp | 10 | ||||
| -rw-r--r-- | llvm/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll | 5 |
2 files changed, 15 insertions, 0 deletions
diff --git a/llvm/lib/VMCore/ConstantFold.cpp b/llvm/lib/VMCore/ConstantFold.cpp index 8c65b563570..3f5c7efbb9a 100644 --- a/llvm/lib/VMCore/ConstantFold.cpp +++ b/llvm/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/llvm/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll b/llvm/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll index debf9a8e5cd..0a40c0ce2c4 100644 --- a/llvm/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll +++ b/llvm/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 + |
