[llvm-commits] [llvm] r114015 - in /llvm/trunk: lib/Analysis/BasicAliasAnalysis.cpp test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll

[Eli Friedman]

Author: efriedma
Date: Wed Sep 15 15:08:03 2010
New Revision: 114015

URL: http://llvm.org/viewvc/llvm-project?rev=114015&view=rev
Log:
PR7959: Handle negative scales in GEPs correctly in BasicAA for non-64-bit
targets.


Added:
    llvm/trunk/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
Modified:
    llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp

Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=114015&r1=114014&r2=114015&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Wed Sep 15 15:08:03 2010
@@ -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) {

Added: llvm/trunk/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll?rev=114015&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll (added)
+++ llvm/trunk/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll Wed Sep 15 15:08:03 2010
@@ -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
+}