Reapply 267210 with fix for PR27490
Original Commit Message
Extend load/store type canonicalization to handle unordered operations
Extend the type canonicalization logic to work for unordered atomic loads and stores. Note that while this change itself is fairly simple and low risk, there's a reasonable chance this will expose problems in the backends by suddenly generating IR they wouldn't have seen before. Anything of this nature will be an existing bug in the backend (you could write an atomic float load), but this will definitely change the frequency with which such cases are encountered. If you see problems, feel free to revert this change, but please make sure you collect a test case.
Note that the concern about lowering is now much less likely. PR27490 proved that we already *were* mucking with the types of ordered atomics and volatiles. As a result, this change doesn't introduce as much new behavior as originally thought.
llvm-svn: 268809
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index 3b0b6b7..6a5d5a6 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -326,7 +326,8 @@
LoadInst *NewLoad = IC.Builder->CreateAlignedLoad(
IC.Builder->CreateBitCast(Ptr, NewTy->getPointerTo(AS)),
- LI.getAlignment(), LI.getName() + Suffix);
+ LI.getAlignment(), LI.isVolatile(), LI.getName() + Suffix);
+ NewLoad->setAtomic(LI.getOrdering(), LI.getSynchScope());
MDBuilder MDB(NewLoad->getContext());
for (const auto &MDPair : MD) {
unsigned ID = MDPair.first;
@@ -398,7 +399,8 @@
StoreInst *NewStore = IC.Builder->CreateAlignedStore(
V, IC.Builder->CreateBitCast(Ptr, V->getType()->getPointerTo(AS)),
- SI.getAlignment());
+ SI.getAlignment(), SI.isVolatile());
+ NewStore->setAtomic(SI.getOrdering(), SI.getSynchScope());
for (const auto &MDPair : MD) {
unsigned ID = MDPair.first;
MDNode *N = MDPair.second;
@@ -456,9 +458,9 @@
/// later. However, it is risky in case some backend or other part of LLVM is
/// relying on the exact type loaded to select appropriate atomic operations.
static Instruction *combineLoadToOperationType(InstCombiner &IC, LoadInst &LI) {
- // FIXME: We could probably with some care handle both volatile and atomic
- // loads here but it isn't clear that this is important.
- if (!LI.isSimple())
+ // FIXME: We could probably with some care handle both volatile and ordered
+ // atomic loads here but it isn't clear that this is important.
+ if (!LI.isUnordered())
return nullptr;
if (LI.use_empty())
@@ -989,9 +991,9 @@
/// the store instruction as otherwise there is no way to signal whether it was
/// combined or not: IC.EraseInstFromFunction returns a null pointer.
static bool combineStoreToValueType(InstCombiner &IC, StoreInst &SI) {
- // FIXME: We could probably with some care handle both volatile and atomic
- // stores here but it isn't clear that this is important.
- if (!SI.isSimple())
+ // FIXME: We could probably with some care handle both volatile and ordered
+ // atomic stores here but it isn't clear that this is important.
+ if (!SI.isUnordered())
return false;
Value *V = SI.getValueOperand();