Fix an overaggressive SimplifyDemandedBits optimization on urem. This
fixes the 254.gap regression on x86 and the 403.gcc regression on x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50537 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 507e6f2..ce052f7 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -1762,11 +1762,12 @@
APInt KnownZero2(BitWidth, 0), KnownOne2(BitWidth, 0);
APInt AllOnes = APInt::getAllOnesValue(BitWidth);
- ComputeMaskedBits(I->getOperand(0), AllOnes,
- KnownZero2, KnownOne2, Depth+1);
+ if (SimplifyDemandedBits(I->getOperand(0), AllOnes,
+ KnownZero2, KnownOne2, Depth+1))
+ return true;
+
uint32_t Leaders = KnownZero2.countLeadingOnes();
- APInt HighZeros = APInt::getHighBitsSet(BitWidth, Leaders);
- if (SimplifyDemandedBits(I->getOperand(1), ~HighZeros,
+ if (SimplifyDemandedBits(I->getOperand(1), AllOnes,
KnownZero2, KnownOne2, Depth+1))
return true;
diff --git a/test/Transforms/InstCombine/urem-simplify-bug.ll b/test/Transforms/InstCombine/urem-simplify-bug.ll
new file mode 100644
index 0000000..15956f2
--- /dev/null
+++ b/test/Transforms/InstCombine/urem-simplify-bug.ll
@@ -0,0 +1,32 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {= or i32 %x, -5 }
+
+@.str = internal constant [5 x i8] c"foo\0A\00" ; <[5 x i8]*> [#uses=1]
+@.str1 = internal constant [5 x i8] c"bar\0A\00" ; <[5 x i8]*> [#uses=1]
+
+define i32 @main() nounwind {
+entry:
+ %x = call i32 @func_11( ) nounwind ; <i32> [#uses=1]
+ %tmp3 = or i32 %x, -5 ; <i32> [#uses=1]
+ %tmp5 = urem i32 251, %tmp3 ; <i32> [#uses=1]
+ %tmp6 = icmp ne i32 %tmp5, 0 ; <i1> [#uses=1]
+ %tmp67 = zext i1 %tmp6 to i32 ; <i32> [#uses=1]
+ %tmp9 = urem i32 %tmp67, 95 ; <i32> [#uses=1]
+ %tmp10 = and i32 %tmp9, 1 ; <i32> [#uses=1]
+ %tmp12 = icmp eq i32 %tmp10, 0 ; <i1> [#uses=1]
+ br i1 %tmp12, label %bb14, label %bb
+
+bb: ; preds = %entry
+ br label %bb15
+
+bb14: ; preds = %entry
+ br label %bb15
+
+bb15: ; preds = %bb14, %bb
+ %iftmp.0.0 = phi i8* [ getelementptr ([5 x i8]* @.str1, i32 0, i32 0), %bb14 ], [ getelementptr ([5 x i8]* @.str, i32 0, i32 0), %bb ] ; <i8*> [#uses=1]
+ %tmp17 = call i32 (i8*, ...)* @printf( i8* %iftmp.0.0 ) nounwind ; <i32> [#uses=0]
+ ret i32 0
+}
+
+declare i32 @func_11()
+
+declare i32 @printf(i8*, ...) nounwind