RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-22 10:42:39 +01:00
Code Issues Projects Releases Wiki Activity

[MemorySSA] Extend removeMemoryAccess API to optimize MemoryPhis.

Browse Source 
Summary:
EarlyCSE needs to optimize MemoryPhis after an access is removed and has
special handling for it. This should be handled by MemorySSA instead.
The default remains that MemoryPhis are *not* optimized after an access
is removed.

Reviewers: george.burgess.iv

Subscribers: sanjoy, jlebar, llvm-commits, Prazek

Differential Revision: https://reviews.llvm.org/D57199

llvm-svn: 352787
This commit is contained in:
Alina Sbirlea 2019-01-31 20:13:47 +00:00
parent ec1c381c57
commit 413877fd20
2 changed files with 24 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/llvm/Analysis/MemorySSAUpdater.h
View File

@ -221,14 +221,14 @@ public:
/// associated with it is erased from the program. For example, if a store or
/// load is simply erased (not replaced), removeMemoryAccess should be called
/// on the MemoryAccess for that store/load.
void removeMemoryAccess(MemoryAccess *);
void removeMemoryAccess(MemoryAccess *, bool OptimizePhis = false);
/// Remove MemoryAccess for a given instruction, if a MemoryAccess exists.
/// This should be called when an instruction (load/store) is deleted from
/// the program.
void removeMemoryAccess(const Instruction *I) {
void removeMemoryAccess(const Instruction *I, bool OptimizePhis = false) {
if (MemoryAccess *MA = MSSA->getMemoryAccess(I))
removeMemoryAccess(MA);
removeMemoryAccess(MA, OptimizePhis);
}
/// Remove all MemoryAcceses in a set of BasicBlocks about to be deleted.

22
lib/Analysis/MemorySSAUpdater.cpp
View File

@ -1051,7 +1051,7 @@ void MemorySSAUpdater::wireOldPredecessorsToNewImmediatePredecessor(
}
}
void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA) {
void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA, bool OptimizePhis) {
assert(!MSSA->isLiveOnEntryDef(MA) &&
"Trying to remove the live on entry def");
// We can only delete phi nodes if they have no uses, or we can replace all
@ -1070,6 +1070,8 @@ void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA) {
NewDefTarget = cast<MemoryUseOrDef>(MA)->getDefiningAccess();
}
SmallSetVector<MemoryPhi *, 4> PhisToCheck;
// Re-point the uses at our defining access
if (!isa<MemoryUse>(MA) && !MA->use_empty()) {
// Reset optimized on users of this store, and reset the uses.
@ -1089,6 +1091,9 @@ void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA) {
Use &U = *MA->use_begin();
if (auto *MUD = dyn_cast<MemoryUseOrDef>(U.getUser()))
MUD->resetOptimized();
if (OptimizePhis)
if (MemoryPhi *MP = dyn_cast<MemoryPhi>(U.getUser()))
PhisToCheck.insert(MP);
U.set(NewDefTarget);
}
}
@ -1097,6 +1102,21 @@ void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA) {
// are doing things here
MSSA->removeFromLookups(MA);
MSSA->removeFromLists(MA);
// Optionally optimize Phi uses. This will recursively remove trivial phis.
if (!PhisToCheck.empty()) {
SmallVector<WeakVH, 16> PhisToOptimize{PhisToCheck.begin(),
PhisToCheck.end()};
PhisToCheck.clear();
unsigned PhisSize = PhisToOptimize.size();
while (PhisSize-- > 0)
if (MemoryPhi *MP =
cast_or_null<MemoryPhi>(PhisToOptimize.pop_back_val())) {
auto OperRange = MP->operands();
tryRemoveTrivialPhi(MP, OperRange);
}
}
}
void MemorySSAUpdater::removeBlocks(