[llvm] r212061 - msan: Stop stripping the 'tail' modifier off of calls

[Reid Kleckner]

Author: rnk
Date: Mon Jun 30 15:12:27 2014
New Revision: 212061

URL: http://llvm.org/viewvc/llvm-project?rev=212061&view=rev
Log:
msan: Stop stripping the 'tail' modifier off of calls

This probably isn't necessary since msan started to unpoison the return
value shadow memory before all calls.

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
    llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp?rev=212061&r1=212060&r2=212061&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp Mon Jun 30 15:12:27 2014
@@ -2272,12 +2272,6 @@ struct MemorySanitizerVisitor : public I
         return;
       }
 
-      // Allow only tail calls with the same types, otherwise
-      // we may have a false positive: shadow for a non-void RetVal
-      // will get propagated to a void RetVal.
-      if (Call->isTailCall() && Call->getType() != Call->getParent()->getType())
-        Call->setTailCall(false);
-
       assert(!isa<IntrinsicInst>(&I) && "intrinsics are handled elsewhere");
 
       // We are going to insert code that relies on the fact that the callee

Modified: llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll?rev=212061&r1=212060&r2=212061&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll (original)
+++ llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll Mon Jun 30 15:12:27 2014
@@ -825,3 +825,17 @@ entry:
 ; CHECK: store i64 16, i64* @__msan_va_arg_overflow_size_tls
 ; CHECK: call void (i32, ...)* @VAArgStructFn
 ; CHECK: ret void
+
+declare i32 @InnerTailCall(i32 %a)
+
+define void @MismatchedReturnTypeTailCall(i32 %a) {
+  %b = tail call i32 @InnerTailCall(i32 %a)
+  ret void
+}
+
+; We used to strip off the 'tail' modifier, but now that we unpoison return slot
+; shadow before the call, we don't need to anymore.
+
+; CHECK-LABEL: define void @MismatchedReturnTypeTailCall
+; CHECK: tail call i32 @InnerTailCall
+; CHECK: ret void