diff options
| -rw-r--r-- | llvm/lib/Analysis/BasicAliasAnalysis.cpp | 3 | ||||
| -rw-r--r-- | llvm/test/Analysis/BasicAA/noalias-wraparound-bug.ll | 24 |
2 files changed, 27 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp index 369b379e64d..ca4c1bfc45f 100644 --- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp +++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp @@ -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); diff --git a/llvm/test/Analysis/BasicAA/noalias-wraparound-bug.ll b/llvm/test/Analysis/BasicAA/noalias-wraparound-bug.ll new file mode 100644 index 00000000000..a75322ed3e9 --- /dev/null +++ b/llvm/test/Analysis/BasicAA/noalias-wraparound-bug.ll @@ -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 +} |
