PR3439: Correct a silly mistake in the SimplifyDemandedUseBits code for

SRem.

llvm-svn: 73598

2 files changed, 19 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index 8dc8659648f..170b47694af 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -1336,7 +1336,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     if (ConstantInt *Rem = dyn_cast<ConstantInt>(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/llvm/test/Transforms/InstCombine/2009-06-16-SRemDemandedBits.ll b/llvm/test/Transforms/InstCombine/2009-06-16-SRemDemandedBits.ll
new file mode 100644
index 00000000000..230e2459055
--- /dev/null
+++ b/llvm/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
+}