From 566f591404ee38a19be1e007a4e88776b82a0128 Mon Sep 17 00:00:00 2001 From: Evgeniy Stepanov Date: Tue, 3 Sep 2013 10:04:11 +0000 Subject: [msan] Fix select instrumentation. Select condition shadow was being ignored resulting in false negatives. This change OR-s sign-extended condition shadow into the result shadow. llvm-svn: 189785 --- llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp') diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp index ae73a2e9c9e..f2cf7a76e54 100644 --- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp +++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp @@ -1743,9 +1743,12 @@ struct MemorySanitizerVisitor : public InstVisitor { void visitSelectInst(SelectInst& I) { IRBuilder<> IRB(&I); - setShadow(&I, IRB.CreateSelect(I.getCondition(), - getShadow(I.getTrueValue()), getShadow(I.getFalseValue()), - "_msprop")); + // a = select b, c, d + // Sa = (sext Sb) | (select b, Sc, Sd) + Value *S = IRB.CreateSelect(I.getCondition(), getShadow(I.getTrueValue()), + getShadow(I.getFalseValue())); + Value *S2 = IRB.CreateSExt(getShadow(I.getCondition()), S->getType()); + setShadow(&I, IRB.CreateOr(S, S2, "_msprop")); if (MS.TrackOrigins) { // Origins are always i32, so any vector conditions must be flattened. // FIXME: consider tracking vector origins for app vectors? -- cgit v1.2.3