IR: add a second ordering operand to cmpxhg for failure

The syntax for "cmpxchg" should now look something like:

	cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic

where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).

rdar://problem/15996804

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203559 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index b13709914bf6..31585d9296ea 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -1567,12 +1567,16 @@ void CppWriter::printInstruction(const Instruction *I,
   }
   case Instruction::AtomicCmpXchg: {
     const AtomicCmpXchgInst *cxi = cast<AtomicCmpXchgInst>(I);
-    StringRef Ordering = ConvertAtomicOrdering(cxi->getOrdering());
+    StringRef SuccessOrdering =
+        ConvertAtomicOrdering(cxi->getSuccessOrdering());
+    StringRef FailureOrdering =
+        ConvertAtomicOrdering(cxi->getFailureOrdering());
     StringRef CrossThread = ConvertAtomicSynchScope(cxi->getSynchScope());
     Out << "AtomicCmpXchgInst* " << iName
         << " = new AtomicCmpXchgInst("
         << opNames[0] << ", " << opNames[1] << ", " << opNames[2] << ", "
-        << Ordering << ", " << CrossThread << ", " << bbname
+        << SuccessOrdering << ", " << FailureOrdering << ", "
+        << CrossThread << ", " << bbname
         << ");";
     nl(Out) << iName << "->setName(\"";
     printEscapedString(cxi->getName());