PR7959: Handle negative scales in GEPs correctly in BasicAA for non-64-bit
targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114015 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 69a1c0c..32a1726 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -386,8 +386,8 @@
// The GEP index scale ("Scale") scales C1*V+C2, yielding (C1*V+C2)*Scale.
// This gives us an aggregate computation of (C1*Scale)*V + C2*Scale.
- BaseOffs += IndexOffset.getZExtValue()*Scale;
- Scale *= IndexScale.getZExtValue();
+ BaseOffs += IndexOffset.getSExtValue()*Scale;
+ Scale *= IndexScale.getSExtValue();
// If we already had an occurrance of this index variable, merge this
@@ -407,7 +407,7 @@
// pointer size.
if (unsigned ShiftBits = 64-TD->getPointerSizeInBits()) {
Scale <<= ShiftBits;
- Scale >>= ShiftBits;
+ Scale = (int64_t)Scale >> ShiftBits;
}
if (Scale) {
diff --git a/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll b/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
new file mode 100644
index 0000000..2b0cd78
--- /dev/null
+++ b/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
@@ -0,0 +1,15 @@
+; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output |& grep {1 may alias}
+; PR7959
+
+target datalayout = "e-p:32:32:32"
+
+define i32 @test(i32* %tab, i32 %indvar) nounwind {
+ %tmp31 = mul i32 %indvar, -2
+ %tmp32 = add i32 %tmp31, 30
+ %t.5 = getelementptr i32* %tab, i32 %tmp32
+ %loada = load i32* %tab
+ store i32 0, i32* %t.5
+ %loadb = load i32* %tab
+ %rval = add i32 %loada, %loadb
+ ret i32 %rval
+}