[llvm-commits] [llvm] r111352 - in /llvm/trunk: lib/Analysis/ValueTracking.cpp test/Analysis/BasicAA/featuretest.ll
Chris Lattner
sabre at nondot.org
Tue Aug 17 21:28:19 PDT 2010
Author: lattner
Date: Tue Aug 17 23:28:19 2010
New Revision: 111352
URL: http://llvm.org/viewvc/llvm-project?rev=111352&view=rev
Log:
fix PR7589: In brief:
gep P, (zext x) != gep P, (sext x)
DecomposeGEPExpression was getting this wrong, confusing
basicaa.
Modified:
llvm/trunk/lib/Analysis/ValueTracking.cpp
llvm/trunk/test/Analysis/BasicAA/featuretest.ll
Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=111352&r1=111351&r2=111352&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Tue Aug 17 23:28:19 2010
@@ -1018,9 +1018,9 @@
}
}
- // 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();
Modified: llvm/trunk/test/Analysis/BasicAA/featuretest.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/featuretest.ll?rev=111352&r1=111351&r2=111352&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/featuretest.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/featuretest.ll Tue Aug 17 23:28:19 2010
@@ -104,3 +104,24 @@
; 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
+}
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