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[BasicAA] Fix for missing must alias (D16343)

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llvm-svn: 259299
This commit is contained in:
Gerolf Hoflehner 2016-01-30 05:52:53 +00:00
parent b4582b54dd
commit 48b45da969
2 changed files with 27 additions and 0 deletions
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3
lib/Analysis/BasicAliasAnalysis.cpp
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@ -465,6 +465,9 @@ static int64_t adjustToPointerSize(int64_t Offset, unsigned PointerSize) {
}
}
// Take care of wrap-arounds
BaseOffs = adjustToPointerSize(BaseOffs, PointerSize);
// Analyze the base pointer next.
V = GEPOp->getOperand(0);
} while (--MaxLookup);

24
test/Analysis/BasicAA/noalias-wraparound-bug.ll Normal file
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@ -0,0 +1,24 @@
; RUN: opt -S -basicaa -gvn < %s | FileCheck %s
target datalayout = "e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128"
target triple = "i386-apple-macosx10.6.0"
; We incorrectly returned noalias in the example below for "tmp5" and
; "tmp12" returning i32 32, since basicaa converted the offsets to 64b
; and missed the wrap-around
define i32 @foo(i8* %buffer) {
entry:
%tmp2 = getelementptr i8, i8* %buffer, i32 -2071408432
%tmp3 = bitcast i8* %tmp2 to i32*
%tmp4 = getelementptr i8, i8* %buffer, i32 128
%tmp5 = bitcast i8* %tmp4 to i32*
store i32 32, i32* %tmp5, align 4
%tmp12 = getelementptr i32, i32* %tmp3, i32 -1629631508
store i32 28, i32* %tmp12, align 4
%tmp13 = getelementptr i8, i8* %buffer, i32 128
%tmp14 = bitcast i8* %tmp13 to i32*
%tmp2083 = load i32, i32* %tmp14, align 4
; CHECK: ret i32 28
ret i32 %tmp2083
}