[llvm] r367352 - [MemorySSA] Extend allowed behavior for simplified instructions.
Alina Sbirlea via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 30 13:10:33 PDT 2019
Author: asbirlea
Date: Tue Jul 30 13:10:33 2019
New Revision: 367352
URL: http://llvm.org/viewvc/llvm-project?rev=367352&view=rev
Log:
[MemorySSA] Extend allowed behavior for simplified instructions.
Summary:
LoopRotate may simplify instructions, leading to the new instructions not having memory accesses created for them.
Allow this behavior, by allowing the new access to be null when the template is null, and looking upwards for the proper defined access when dealing with simplified instructions.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65338
Added:
llvm/trunk/test/Analysis/MemorySSA/loop-rotate-simplified-clone.ll
Modified:
llvm/trunk/include/llvm/Analysis/MemorySSA.h
llvm/trunk/lib/Analysis/MemorySSA.cpp
llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp
Modified: llvm/trunk/include/llvm/Analysis/MemorySSA.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/MemorySSA.h?rev=367352&r1=367351&r2=367352&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/MemorySSA.h (original)
+++ llvm/trunk/include/llvm/Analysis/MemorySSA.h Tue Jul 30 13:10:33 2019
@@ -830,7 +830,8 @@ protected:
void insertIntoListsBefore(MemoryAccess *, const BasicBlock *,
AccessList::iterator);
MemoryUseOrDef *createDefinedAccess(Instruction *, MemoryAccess *,
- const MemoryUseOrDef *Template = nullptr);
+ const MemoryUseOrDef *Template = nullptr,
+ bool CreationMustSucceed = true);
private:
template <class AliasAnalysisType> class ClobberWalkerBase;
Modified: llvm/trunk/lib/Analysis/MemorySSA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemorySSA.cpp?rev=367352&r1=367351&r2=367352&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemorySSA.cpp (original)
+++ llvm/trunk/lib/Analysis/MemorySSA.cpp Tue Jul 30 13:10:33 2019
@@ -1687,13 +1687,15 @@ MemoryPhi *MemorySSA::createMemoryPhi(Ba
MemoryUseOrDef *MemorySSA::createDefinedAccess(Instruction *I,
MemoryAccess *Definition,
- const MemoryUseOrDef *Template) {
+ const MemoryUseOrDef *Template,
+ bool CreationMustSucceed) {
assert(!isa<PHINode>(I) && "Cannot create a defined access for a PHI");
MemoryUseOrDef *NewAccess = createNewAccess(I, AA, Template);
- assert(
- NewAccess != nullptr &&
- "Tried to create a memory access for a non-memory touching instruction");
- NewAccess->setDefiningAccess(Definition);
+ if (CreationMustSucceed)
+ assert(NewAccess != nullptr && "Tried to create a memory access for a "
+ "non-memory touching instruction");
+ if (NewAccess)
+ NewAccess->setDefiningAccess(Definition);
return NewAccess;
}
Modified: llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp?rev=367352&r1=367351&r2=367352&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp (original)
+++ llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp Tue Jul 30 13:10:33 2019
@@ -480,29 +480,47 @@ void MemorySSAUpdater::removeDuplicatePh
}
}
+static MemoryAccess *getNewDefiningAccessForClone(MemoryAccess *MA,
+ const ValueToValueMapTy &VMap,
+ PhiToDefMap &MPhiMap,
+ bool CloneWasSimplified,
+ MemorySSA *MSSA) {
+ MemoryAccess *InsnDefining = MA;
+ if (MemoryDef *DefMUD = dyn_cast<MemoryDef>(InsnDefining)) {
+ if (!MSSA->isLiveOnEntryDef(DefMUD)) {
+ Instruction *DefMUDI = DefMUD->getMemoryInst();
+ assert(DefMUDI && "Found MemoryUseOrDef with no Instruction.");
+ if (Instruction *NewDefMUDI =
+ cast_or_null<Instruction>(VMap.lookup(DefMUDI))) {
+ InsnDefining = MSSA->getMemoryAccess(NewDefMUDI);
+ if (!CloneWasSimplified)
+ assert(InsnDefining && "Defining instruction cannot be nullptr.");
+ else if (!InsnDefining || isa<MemoryUse>(InsnDefining)) {
+ // The clone was simplified, it's no longer a MemoryDef, look up.
+ auto DefIt = DefMUD->getDefsIterator();
+ // Since simplified clones only occur in single block cloning, a
+ // previous definition must exist, otherwise NewDefMUDI would not
+ // have been found in VMap.
+ assert(DefIt != MSSA->getBlockDefs(DefMUD->getBlock())->begin() &&
+ "Previous def must exist");
+ InsnDefining = getNewDefiningAccessForClone(
+ &*(--DefIt), VMap, MPhiMap, CloneWasSimplified, MSSA);
+ }
+ }
+ }
+ } else {
+ MemoryPhi *DefPhi = cast<MemoryPhi>(InsnDefining);
+ if (MemoryAccess *NewDefPhi = MPhiMap.lookup(DefPhi))
+ InsnDefining = NewDefPhi;
+ }
+ assert(InsnDefining && "Defining instruction cannot be nullptr.");
+ return InsnDefining;
+}
+
void MemorySSAUpdater::cloneUsesAndDefs(BasicBlock *BB, BasicBlock *NewBB,
const ValueToValueMapTy &VMap,
PhiToDefMap &MPhiMap,
bool CloneWasSimplified) {
- auto GetNewDefiningAccess = [&](MemoryAccess *MA) -> MemoryAccess * {
- MemoryAccess *InsnDefining = MA;
- if (MemoryUseOrDef *DefMUD = dyn_cast<MemoryUseOrDef>(InsnDefining)) {
- if (!MSSA->isLiveOnEntryDef(DefMUD)) {
- Instruction *DefMUDI = DefMUD->getMemoryInst();
- assert(DefMUDI && "Found MemoryUseOrDef with no Instruction.");
- if (Instruction *NewDefMUDI =
- cast_or_null<Instruction>(VMap.lookup(DefMUDI)))
- InsnDefining = MSSA->getMemoryAccess(NewDefMUDI);
- }
- } else {
- MemoryPhi *DefPhi = cast<MemoryPhi>(InsnDefining);
- if (MemoryAccess *NewDefPhi = MPhiMap.lookup(DefPhi))
- InsnDefining = NewDefPhi;
- }
- assert(InsnDefining && "Defining instruction cannot be nullptr.");
- return InsnDefining;
- };
-
const MemorySSA::AccessList *Acc = MSSA->getBlockAccesses(BB);
if (!Acc)
return;
@@ -519,9 +537,13 @@ void MemorySSAUpdater::cloneUsesAndDefs(
if (Instruction *NewInsn =
dyn_cast_or_null<Instruction>(VMap.lookup(Insn))) {
MemoryAccess *NewUseOrDef = MSSA->createDefinedAccess(
- NewInsn, GetNewDefiningAccess(MUD->getDefiningAccess()),
- CloneWasSimplified ? nullptr : MUD);
- MSSA->insertIntoListsForBlock(NewUseOrDef, NewBB, MemorySSA::End);
+ NewInsn,
+ getNewDefiningAccessForClone(MUD->getDefiningAccess(), VMap,
+ MPhiMap, CloneWasSimplified, MSSA),
+ /*Template=*/CloneWasSimplified ? nullptr : MUD,
+ /*CreationMustSucceed=*/CloneWasSimplified ? false : true);
+ if (NewUseOrDef)
+ MSSA->insertIntoListsForBlock(NewUseOrDef, NewBB, MemorySSA::End);
}
}
}
Added: llvm/trunk/test/Analysis/MemorySSA/loop-rotate-simplified-clone.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/MemorySSA/loop-rotate-simplified-clone.ll?rev=367352&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/MemorySSA/loop-rotate-simplified-clone.ll (added)
+++ llvm/trunk/test/Analysis/MemorySSA/loop-rotate-simplified-clone.ll Tue Jul 30 13:10:33 2019
@@ -0,0 +1,29 @@
+; RUN: opt -verify-memoryssa -enable-mssa-loop-dependency -loop-rotate %s -S | FileCheck %s
+; REQUIRES: asserts
+
+; CHECK-LABEL: @test()
+define dso_local void @test() {
+entry:
+ br label %preheader
+
+preheader:
+ br label %l39
+
+l39:
+ %v40 = phi float (float)* [ @foo, %preheader ], [ %v43, %crit_edge ]
+ %v41 = call float %v40(float undef)
+ %v42 = load i32, i32* undef, align 8
+ br i1 undef, label %crit_edge, label %loopexit
+
+crit_edge:
+ %v43 = load float (float)*, float (float)** undef, align 8
+ br label %l39
+
+loopexit:
+ unreachable
+}
+
+; Function Attrs: readnone
+declare dso_local float @foo(float) #0 align 32
+
+attributes #0 = { readnone }
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