[llvm] 71792dc - [NFC][msan] Workaround arg evaluation order diff GCC vs Clang (#113378)

[via llvm-commits]

Author: Vitaly Buka
Date: 2024-10-22T13:31:46-07:00
New Revision: 71792dc570c5b0eca0937efbd57d9ea1457dc87f

URL: https://github.com/llvm/llvm-project/commit/71792dc570c5b0eca0937efbd57d9ea1457dc87f
DIFF: https://github.com/llvm/llvm-project/commit/71792dc570c5b0eca0937efbd57d9ea1457dc87f.diff

LOG: [NFC][msan] Workaround arg evaluation order diff GCC vs Clang (#113378)

Added: 
    

Modified: 
    llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 9e174e2415e719..63810e875ae0a2 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -2750,12 +2750,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
     // its undefined bits. Let [b0, b1] be the interval of possible values of B.
     // Then (A cmp B) is defined iff (a0 cmp b1) == (a1 cmp b0).
     bool IsSigned = I.isSigned();
-    Value *S1 = IRB.CreateICmp(I.getPredicate(),
-                               getLowestPossibleValue(IRB, A, Sa, IsSigned),
-                               getHighestPossibleValue(IRB, B, Sb, IsSigned));
-    Value *S2 = IRB.CreateICmp(I.getPredicate(),
-                               getHighestPossibleValue(IRB, A, Sa, IsSigned),
-                               getLowestPossibleValue(IRB, B, Sb, IsSigned));
+    Value *Amin = getLowestPossibleValue(IRB, A, Sa, IsSigned);
+    Value *Bmax = getHighestPossibleValue(IRB, B, Sb, IsSigned);
+    Value *S1 = IRB.CreateICmp(I.getPredicate(), Amin, Bmax);
+    Value *Amax = getHighestPossibleValue(IRB, A, Sa, IsSigned);
+    Value *Bmin = getLowestPossibleValue(IRB, B, Sb, IsSigned);
+    Value *S2 = IRB.CreateICmp(I.getPredicate(), Amax, Bmin);
     Value *Si = IRB.CreateXor(S1, S2);
     setShadow(&I, Si);
     setOriginForNaryOp(I);