diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 31 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2008-07-10-CastSextBool.ll | 8 |
2 files changed, 23 insertions, 16 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index e0e3f49be1..8cc7c05425 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -5230,7 +5230,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { // See if we are doing a comparison between a constant and an instruction that // can be folded into the comparison. if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { - Value *A, *B; + Value *A, *B; // (icmp ne/eq (sub A B) 0) -> (icmp ne/eq A, B) if (I.isEquality() && CI->isNullValue() && @@ -5396,6 +5396,8 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { return ReplaceInstUsesWith(I, ConstantInt::getTrue()); if (Min.sgt(RHSVal)) return ReplaceInstUsesWith(I, ConstantInt::getFalse()); + if (Max == RHSVal) // A <s MAX -> A != MAX + return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1); break; case ICmpInst::ICMP_SGT: if (Min.sgt(RHSVal)) @@ -6300,12 +6302,11 @@ Instruction *InstCombiner::visitICmpInstWithCastAndCast(ICmpInst &ICI) { // %B = icmp ugt short %X, 1330 // because %A may have negative value. // - // However, it is OK if SrcTy is bool (See cast-set.ll testcase) - // OR operation is EQ/NE. - if (isSignedExt == isSignedCmp || SrcTy == Type::Int1Ty || ICI.isEquality()) + // However, we allow this when the compare is EQ/NE, because they are + // signless. + if (isSignedExt == isSignedCmp || ICI.isEquality()) return new ICmpInst(ICI.getPredicate(), LHSCIOp, Res1); - else - return 0; + return 0; } // The re-extended constant changed so the constant cannot be represented @@ -6343,17 +6344,15 @@ Instruction *InstCombiner::visitICmpInstWithCastAndCast(ICmpInst &ICI) { // Finally, return the value computed. if (ICI.getPredicate() == ICmpInst::ICMP_ULT || - ICI.getPredicate() == ICmpInst::ICMP_SLT) { + ICI.getPredicate() == ICmpInst::ICMP_SLT) return ReplaceInstUsesWith(ICI, Result); - } else { - assert((ICI.getPredicate()==ICmpInst::ICMP_UGT || - ICI.getPredicate()==ICmpInst::ICMP_SGT) && - "ICmp should be folded!"); - if (Constant *CI = dyn_cast<Constant>(Result)) - return ReplaceInstUsesWith(ICI, ConstantExpr::getNot(CI)); - else - return BinaryOperator::CreateNot(Result); - } + + assert((ICI.getPredicate()==ICmpInst::ICMP_UGT || + ICI.getPredicate()==ICmpInst::ICMP_SGT) && + "ICmp should be folded!"); + if (Constant *CI = dyn_cast<Constant>(Result)) + return ReplaceInstUsesWith(ICI, ConstantExpr::getNot(CI)); + return BinaryOperator::CreateNot(Result); } Instruction *InstCombiner::visitShl(BinaryOperator &I) { diff --git a/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll b/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll new file mode 100644 index 0000000000..f5efefb0a0 --- /dev/null +++ b/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll @@ -0,0 +1,8 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {%C = xor i1 %A, true} +; PR2539 + +define i1 @test(i1 %A) { + %B = zext i1 %A to i32 + %C = icmp slt i32 %B, 1 + ret i1 %C +} |