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
This commit is contained in:
Tim Northover
2014-03-11 10:48:52 +00:00
parent fb411c8b8c
commit ca396e391e
60 changed files with 489 additions and 288 deletions

View File

@ -2882,7 +2882,8 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
break;
}
case bitc::FUNC_CODE_INST_CMPXCHG: {
// CMPXCHG:[ptrty, ptr, cmp, new, vol, ordering, synchscope]
// CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, synchscope,
// failureordering]
unsigned OpNum = 0;
Value *Ptr, *Cmp, *New;
if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
@ -2890,13 +2891,22 @@ error_code BitcodeReader::ParseFunctionBody(Function *F) {
cast<PointerType>(Ptr->getType())->getElementType(), Cmp) ||
popValue(Record, OpNum, NextValueNo,
cast<PointerType>(Ptr->getType())->getElementType(), New) ||
OpNum+3 != Record.size())
(OpNum + 3 != Record.size() && OpNum + 4 != Record.size()))
return Error(InvalidRecord);
AtomicOrdering Ordering = GetDecodedOrdering(Record[OpNum+1]);
if (Ordering == NotAtomic || Ordering == Unordered)
AtomicOrdering SuccessOrdering = GetDecodedOrdering(Record[OpNum+1]);
if (SuccessOrdering == NotAtomic || SuccessOrdering == Unordered)
return Error(InvalidRecord);
SynchronizationScope SynchScope = GetDecodedSynchScope(Record[OpNum+2]);
I = new AtomicCmpXchgInst(Ptr, Cmp, New, Ordering, SynchScope);
AtomicOrdering FailureOrdering;
if (Record.size() < 7)
FailureOrdering =
AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrdering);
else
FailureOrdering = GetDecodedOrdering(Record[OpNum+3]);
I = new AtomicCmpXchgInst(Ptr, Cmp, New, SuccessOrdering, FailureOrdering,
SynchScope);
cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
InstructionList.push_back(I);
break;