[msan] Workaround for invalid origins in shufflevector.

Makes origin propagation ignore literal undef operands, and,
in general, any operand we don't have origin for.

https://code.google.com/p/memory-sanitizer/issues/detail?id=56

llvm-svn: 210472

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/test/Instrumentation/MemorySanitizer/missing_origin.ll b/llvm/test/Instrumentation/MemorySanitizer/missing_origin.ll
new file mode 100644
index 00000000000..d8addce0dae
--- /dev/null
+++ b/llvm/test/Instrumentation/MemorySanitizer/missing_origin.ll
@@ -0,0 +1,19 @@
+; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=1 -S | FileCheck -check-prefix=CHECK -check-prefix=CHECK %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Test that result origin is directy propagated from the argument,
+; and is not affected by all the literal undef operands.
+; https://code.google.com/p/memory-sanitizer/issues/detail?id=56
+
+define <4 x i32> @Shuffle(<4 x i32> %x) nounwind uwtable sanitize_memory {
+entry:
+  %y = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
+  ret <4 x i32> %y
+}
+
+; CHECK-LABEL: @Shuffle(
+; CHECK: [[A:%.*]] = load i32* {{.*}}@__msan_param_origin_tls,
+; CHECK: store i32 [[A]], i32* @__msan_retval_origin_tls
+; CHECK: ret <4 x i32>