mirrors/llvm-project
0
0
Fork 0
mirror of https://github.com/llvm/llvm-project.git synced 2025-04-18 17:56:50 +00:00
Code Issues Projects Releases Wiki Activity

[LICM] allow MemoryAccess creation failure (#116813)

Browse Source 
Fixes #116809.

After running some passes (SimpleLoopUnswitch, LoopInstSimplify, etc.),
MemorySSA might be outdated, and the instruction `I` may have become a
non-memory touching instruction.

LICM has already handled this, but it does not pass
`CreationMustSucceed=false` to `createDefinedAccess`.

(cherry picked from commit 18b02bbf441660683df7f3925946984203d49bab)
This commit is contained in:
DianQK 2024-11-20 19:52:51 +08:00 committed by Tobias Hieta
parent e80925b5eb
commit 5bd0474d1c
No known key found for this signature in database
GPG Key ID: 44F2485E45D59042
4 changed files with 70 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
llvm/include/llvm/Analysis/MemorySSAUpdater.h
View File

@ -192,6 +192,11 @@ public:
const BasicBlock *BB,
MemorySSA::InsertionPlace Point);
MemoryAccess *createMemoryAccessInBB(Instruction *I, MemoryAccess *Definition,
const BasicBlock *BB,
MemorySSA::InsertionPlace Point,
bool CreationMustSucceed);
/// Create a MemoryAccess in MemorySSA before an existing MemoryAccess.
///
/// See createMemoryAccessInBB() for usage details.

13
llvm/lib/Analysis/MemorySSAUpdater.cpp
View File

@ -1404,8 +1404,17 @@ void MemorySSAUpdater::changeToUnreachable(const Instruction *I) {
MemoryAccess *MemorySSAUpdater::createMemoryAccessInBB(
Instruction *I, MemoryAccess *Definition, const BasicBlock *BB,
MemorySSA::InsertionPlace Point) {
MemoryUseOrDef *NewAccess = MSSA->createDefinedAccess(I, Definition);
MSSA->insertIntoListsForBlock(NewAccess, BB, Point);
return createMemoryAccessInBB(I, Definition, BB, Point,
/*CreationMustSucceed=*/true);
}
MemoryAccess *MemorySSAUpdater::createMemoryAccessInBB(
Instruction *I, MemoryAccess *Definition, const BasicBlock *BB,
MemorySSA::InsertionPlace Point, bool CreationMustSucceed) {
MemoryUseOrDef *NewAccess = MSSA->createDefinedAccess(
I, Definition, /*Template=*/nullptr, CreationMustSucceed);
if (NewAccess)
MSSA->insertIntoListsForBlock(NewAccess, BB, Point);
return NewAccess;
}

5
llvm/lib/Transforms/Scalar/LICM.cpp
View File

@ -1464,8 +1464,11 @@ static Instruction *cloneInstructionInExitBlock(
if (MSSAU.getMemorySSA()->getMemoryAccess(&I)) {
// Create a new MemoryAccess and let MemorySSA set its defining access.
// After running some passes, MemorySSA might be outdated, and the
// instruction `I` may have become a non-memory touching instruction.
MemoryAccess *NewMemAcc = MSSAU.createMemoryAccessInBB(
New, nullptr, New->getParent(), MemorySSA::Beginning);
New, nullptr, New->getParent(), MemorySSA::Beginning,
/*CreationMustSucceed=*/false);
if (NewMemAcc) {
if (auto *MemDef = dyn_cast<MemoryDef>(NewMemAcc))
MSSAU.insertDef(MemDef, /*RenameUses=*/true);

50
llvm/test/Transforms/LICM/PR116813-memoryssa-outdated.ll Normal file
View File

@ -0,0 +1,50 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes='loop-mssa(simple-loop-unswitch<nontrivial>,licm)' -verify-memoryssa -S < %s | FileCheck %s
; Check that running LICM after SimpleLoopUnswitch does not result in a crash.
define i32 @foo(i1 %arg, ptr %arg1) {
; CHECK-LABEL: define i32 @foo(
; CHECK-SAME: i1 [[ARG:%.*]], ptr [[ARG1:%.*]]) {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[ARG_FR:%.*]] = freeze i1 [[ARG]]
; CHECK-NEXT: br i1 [[ARG_FR]], label %[[START_SPLIT_US:.*]], label %[[START_SPLIT:.*]]
; CHECK: [[START_SPLIT_US]]:
; CHECK-NEXT: br label %[[LOOP_US:.*]]
; CHECK: [[LOOP_US]]:
; CHECK-NEXT: br label %[[BB0:.*]]
; CHECK: [[BB0]]:
; CHECK-NEXT: br label %[[BB1:.*]]
; CHECK: [[BB1]]:
; CHECK-NEXT: [[UNSWITCHED_SELECT_US:%.*]] = phi ptr [ [[ARG1]], %[[BB0]] ]
; CHECK-NEXT: [[I3_US:%.*]] = call i32 [[UNSWITCHED_SELECT_US]]()
; CHECK-NEXT: br i1 true, label %[[LOOP_US]], label %[[RET_SPLIT_US:.*]]
; CHECK: [[RET_SPLIT_US]]:
; CHECK-NEXT: [[I3_LCSSA_US:%.*]] = phi i32 [ [[I3_US]], %[[BB1]] ]
; CHECK-NEXT: br label %[[RET:.*]]
; CHECK: [[START_SPLIT]]:
; CHECK-NEXT: br label %[[LOOP:.*]]
; CHECK: [[LOOP]]:
; CHECK-NEXT: br label %[[BB2:.*]]
; CHECK: [[BB2]]:
; CHECK-NEXT: br i1 false, label %[[LOOP]], label %[[RET_SPLIT:.*]]
; CHECK: [[RET_SPLIT]]:
; CHECK-NEXT: [[I3_LE:%.*]] = call i32 @bar()
; CHECK-NEXT: br label %[[RET]]
; CHECK: [[RET]]:
; CHECK-NEXT: [[DOTUS_PHI:%.*]] = phi i32 [ [[I3_LE]], %[[RET_SPLIT]] ], [ [[I3_LCSSA_US]], %[[RET_SPLIT_US]] ]
; CHECK-NEXT: ret i32 [[DOTUS_PHI]]
;
start:
br label %loop
loop: ; preds = %loop, %bb
%i = select i1 %arg, ptr %arg1, ptr @bar
%i3 = call i32 %i()
br i1 %arg, label %loop, label %ret
ret: ; preds = %loop
ret i32 %i3
}
declare i32 @bar() nounwind willreturn memory(none)