From 69086b2962b16a9e78aea0605202c5ea126049ae Mon Sep 17 00:00:00 2001
From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Tue, 3 Sep 2013 13:05:29 +0000
Subject: [PATCH] [msan] Fix handling of select with struct arguments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189796 91177308-0d34-0410-b5e6-96231b3b80d8
---
.../Instrumentation/MemorySanitizer.cpp | 17 ++++++++++++++---
.../MemorySanitizer/msan_basic.ll | 13 +++++++++++++
2 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index f2cf7a76e54..e9b78acbfe5 100644
--- a/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -1744,11 +1744,22 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
void visitSelectInst(SelectInst& I) {
IRBuilder<> IRB(&I);
// 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 (I.getType()->isAggregateType()) {
+ // To avoid "sign extending" i1 to an arbitrary aggregate type, we just do
+ // an extra "select". This results in much more compact IR.
+ // Sa = select Sb, poisoned, (select b, Sc, Sd)
+ S = IRB.CreateSelect(getShadow(I.getCondition()),
+ getPoisonedShadow(getShadowTy(I.getType())), S,
+ "_msprop_select_agg");
+ } else {
+ // Sa = (sext Sb) | (select b, Sc, Sd)
+ S = IRB.CreateOr(
+ S, IRB.CreateSExt(getShadow(I.getCondition()), S->getType()),
+ "_msprop_select");
+ }
+ setShadow(&I, S);
if (MS.TrackOrigins) {
// Origins are always i32, so any vector conditions must be flattened.
// FIXME: consider tracking vector origins for app vectors?
diff --git a/test/Instrumentation/MemorySanitizer/msan_basic.ll b/test/Instrumentation/MemorySanitizer/msan_basic.ll
index 466e2528dd9..e87bf530273 100644
--- a/test/Instrumentation/MemorySanitizer/msan_basic.ll
+++ b/test/Instrumentation/MemorySanitizer/msan_basic.ll
@@ -290,6 +290,19 @@ entry:
; CHECK-ORIGINS: ret <8 x i16>
+define { i64, i64 } @SelectStruct(i1 zeroext %x, { i64, i64 } %a, { i64, i64 } %b) readnone sanitize_memory {
+entry:
+ %c = select i1 %x, { i64, i64 } %a, { i64, i64 } %b
+ ret { i64, i64 } %c
+}
+
+; CHECK: @SelectStruct
+; CHECK: select i1 {{.*}}, { i64, i64 }
+; CHECK-NEXT: select i1 {{.*}}, { i64, i64 } { i64 -1, i64 -1 }, { i64, i64 }
+; CHECK-NEXT: select i1 {{.*}}, { i64, i64 }
+; CHECK: ret { i64, i64 }
+
+
define i8* @IntToPtr(i64 %x) nounwind uwtable readnone sanitize_memory {
entry:
%0 = inttoptr i64 %x to i8*