diff options
| -rw-r--r-- | llvm/lib/Target/README.txt | 26 | ||||
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 20 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/zext-fold.ll | 1 |
3 files changed, 20 insertions, 27 deletions
diff --git a/llvm/lib/Target/README.txt b/llvm/lib/Target/README.txt index c9f11b935cd..23572cd6bc5 100644 --- a/llvm/lib/Target/README.txt +++ b/llvm/lib/Target/README.txt @@ -775,32 +775,6 @@ be done safely if "b" isn't modified between the strlen and memcpy of course. //===---------------------------------------------------------------------===// -define i32 @test2(float %X, float %Y) { -entry: - %tmp3 = fcmp uno float %X, %Y ; <i1> [#uses=1] - %tmp34 = zext i1 %tmp3 to i8 ; <i8> [#uses=1] - %tmp = xor i8 %tmp34, 1 ; <i8> [#uses=1] - %toBoolnot5 = zext i8 %tmp to i32 ; <i32> [#uses=1] - ret i32 %toBoolnot5 -} - -could be optimized further. Instcombine should use its bitwise analysis to -collapse the zext/xor/zext structure to an xor/zext and then remove the -xor by reversing the fcmp. - -Desired output: - -define i32 @test2(float %X, float %Y) { -entry: - %tmp3 = fcmp ord float %X, %Y ; <i1> [#uses=1] - %tmp34 = zext i1 %tmp3 to i32 ; <i32> [#uses=1] - ret i32 %tmp34 -} - -To fix this, we need to make CanEvaluateInDifferentType smarter. - -//===---------------------------------------------------------------------===// - We should be able to evaluate this loop: int test(int x_offs) { diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 6222d2ae49b..89c49c1a6e4 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -5013,6 +5013,25 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) { FCI->getOperand(0), FCI->getOperand(1)); } + // 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) { + if (RHS == ConstantExpr::getCast(Opcode, ConstantInt::getTrue(), + Op0C->getDestTy())) { + Instruction *NewCI = InsertNewInstBefore(CmpInst::Create( + CI->getOpcode(), CI->getInversePredicate(), + CI->getOperand(0), CI->getOperand(1)), I); + NewCI->takeName(CI); + return CastInst::Create(Opcode, NewCI, Op0C->getType()); + } + } + } + } + } + if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) { // ~(c-X) == X-c-1 == X+(-c-1) if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue()) @@ -5206,6 +5225,7 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) { } } } + return Changed ? &I : 0; } diff --git a/llvm/test/Transforms/InstCombine/zext-fold.ll b/llvm/test/Transforms/InstCombine/zext-fold.ll index 690a2275e06..27ea46061b0 100644 --- a/llvm/test/Transforms/InstCombine/zext-fold.ll +++ b/llvm/test/Transforms/InstCombine/zext-fold.ll @@ -1,6 +1,5 @@ ; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {zext } | count 1 ; PR1570 -; XFAIL: * define i32 @test2(float %X, float %Y) { entry: |
