From a999a511f782badfbfe98f1cdf7e92d4824f7a46 Mon Sep 17 00:00:00 2001 From: Eli Friedman Date: Wed, 17 Jun 2009 02:57:36 +0000 Subject: [PATCH] PR3439: Correct a silly mistake in the SimplifyDemandedUseBits code for SRem. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73598 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/InstructionCombining.cpp | 2 +- .../InstCombine/2009-06-16-SRemDemandedBits.ll | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) create mode 100644 test/Transforms/InstCombine/2009-06-16-SRemDemandedBits.ll diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 8dc8659648f..170b47694af 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1336,7 +1336,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, if (ConstantInt *Rem = dyn_cast(I->getOperand(1))) { APInt RA = Rem->getValue().abs(); if (RA.isPowerOf2()) { - if (DemandedMask.ule(RA)) // srem won't affect demanded bits + if (DemandedMask.ult(RA)) // srem won't affect demanded bits return I->getOperand(0); APInt LowBits = RA - 1; diff --git a/test/Transforms/InstCombine/2009-06-16-SRemDemandedBits.ll b/test/Transforms/InstCombine/2009-06-16-SRemDemandedBits.ll new file mode 100644 index 00000000000..230e2459055 --- /dev/null +++ b/test/Transforms/InstCombine/2009-06-16-SRemDemandedBits.ll @@ -0,0 +1,18 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep srem +; PR3439 + +define i32 @a(i32 %x) nounwind { +entry: + %rem = srem i32 %x, 2 + %and = and i32 %rem, 2 + ret i32 %and +} +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep srem +; PR3439 + +define i32 @a(i32 %x) nounwind { +entry: + %rem = srem i32 %x, 2 + %and = and i32 %rem, 2 + ret i32 %and +} -- 2.11.0