diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 50dc6d41c1e..145aa92a60e 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -1551,8 +1551,7 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond, // Check stride constant and the comparision constant signs to detect // overflow. - if (ICmpInst::isSignedPredicate(Predicate) && - (CmpVal & SignBit) != (CmpSSInt & SignBit)) + if ((CmpVal & SignBit) != (CmpSSInt & SignBit)) return Cond; // Look for a suitable stride / iv as replacement. diff --git a/test/Transforms/LoopStrengthReduce/2008-09-09-Overflow.ll b/test/Transforms/LoopStrengthReduce/2008-09-09-Overflow.ll new file mode 100644 index 00000000000..703aebef7ca --- /dev/null +++ b/test/Transforms/LoopStrengthReduce/2008-09-09-Overflow.ll @@ -0,0 +1,48 @@ +; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep phi | count 2 +; PR 2779 +@g_19 = common global i32 0 ; [#uses=3] +@"\01LC" = internal constant [4 x i8] c"%d\0A\00" ; <[4 x i8]*> [#uses=1] + +define i32 @func_8(i8 zeroext %p_9) nounwind { +entry: + ret i32 1 +} + +define i32 @func_3(i8 signext %p_5) nounwind { +entry: + ret i32 1 +} + +define void @func_1() nounwind { +entry: + br label %bb + +bb: ; preds = %bb, %entry + %indvar = phi i16 [ 0, %entry ], [ %indvar.next, %bb ] ; [#uses=2] + %tmp = sub i16 0, %indvar ; [#uses=1] + %tmp27 = trunc i16 %tmp to i8 ; [#uses=1] + load i32* @g_19, align 4 ; :0 [#uses=2] + add i32 %0, 1 ; :1 [#uses=1] + store i32 %1, i32* @g_19, align 4 + trunc i32 %0 to i8 ; :2 [#uses=1] + tail call i32 @func_8( i8 zeroext %2 ) nounwind ; :3 [#uses=0] + shl i8 %tmp27, 2 ; :4 [#uses=1] + add i8 %4, -112 ; :5 [#uses=1] + tail call i32 @func_3( i8 signext %5 ) nounwind ; :6 [#uses=0] + %indvar.next = add i16 %indvar, 1 ; [#uses=2] + %exitcond = icmp eq i16 %indvar.next, -28 ; [#uses=1] + br i1 %exitcond, label %return, label %bb + +return: ; preds = %bb + ret void +} + +define i32 @main() nounwind { +entry: + tail call void @func_1( ) nounwind + load i32* @g_19, align 4 ; :0 [#uses=1] + tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @"\01LC", i32 0, i32 0), i32 %0 ) nounwind ; :1 [#uses=0] + ret i32 0 +} + +declare i32 @printf(i8*, ...) nounwind