diff options
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 6 | ||||
| -rw-r--r-- | test/Analysis/BasicAA/featuretest.ll | 21 |
2 files changed, 24 insertions, 3 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index b4c9884a20..cf20e07040 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -1018,9 +1018,9 @@ static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset, } } - // Since clients don't care about the high bits of the value, just scales and - // offsets, we can look through extensions. - if (isa<SExtInst>(V) || isa<ZExtInst>(V)) { + // Since GEP indices are sign extended anyway, we don't care about the high + // bits of a sign extended value - just scales and offsets. + if (isa<SExtInst>(V)) { Value *CastOp = cast<CastInst>(V)->getOperand(0); unsigned OldWidth = Scale.getBitWidth(); unsigned SmallWidth = CastOp->getType()->getPrimitiveSizeInBits(); diff --git a/test/Analysis/BasicAA/featuretest.ll b/test/Analysis/BasicAA/featuretest.ll index ce71e9af95..47d278fab1 100644 --- a/test/Analysis/BasicAA/featuretest.ll +++ b/test/Analysis/BasicAA/featuretest.ll @@ -104,3 +104,24 @@ define i32 @constexpr_test() { ; CHECK: @constexpr_test ; CHECK: ret i32 0 } + + + +; PR7589 +; These two index expressions are different, this cannot be CSE'd. +define i16 @zext_sext_confusion(i16* %row2col, i5 %j) nounwind{ +entry: + %sum5.cast = zext i5 %j to i64 ; <i64> [#uses=1] + %P1 = getelementptr i16* %row2col, i64 %sum5.cast + %row2col.load.1.2 = load i16* %P1, align 1 ; <i16> [#uses=1] + + %sum13.cast31 = sext i5 %j to i6 ; <i6> [#uses=1] + %sum13.cast = zext i6 %sum13.cast31 to i64 ; <i64> [#uses=1] + %P2 = getelementptr i16* %row2col, i64 %sum13.cast + %row2col.load.1.6 = load i16* %P2, align 1 ; <i16> [#uses=1] + + %.ret = sub i16 %row2col.load.1.6, %row2col.load.1.2 ; <i16> [#uses=1] + ret i16 %.ret +; CHECK: @zext_sext_confusion +; CHECK: ret i16 %.ret +} |