RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-01-31 20:51:52 +01:00
Code Issues Projects Releases Wiki Activity

[DSE] Do not scan users of memory terminators for further reads.

Browse Source 
isMemTerminator checks if the current def is a memory terminator that
terminates the memory pointed to by DefLoc. We do not have to add any of
their users to the worklist, because the follow-on users cannot read the
memory in question.

This leads to more stores eliminated in the presence of lifetime calls.
Previously we added the users of those intrinsics to the worklist,
limiting elimination.

In terms of removed stores, this gives a nice boost on some benchmarks
(MultiSource/SPEC2000/SPEC2006 on X86 with -flto -O3):

Same hash: 205 (filtered out)
Remaining: 32
Metric: dse.NumFastStores

Program                                          base   patch   diff
 test-suite...000/197.parser/197.parser.test     4.00    8.00  100.0%
 test-suite...rolangs-C++/family/family.test     4.00    7.00  75.0%
 test-suite...marks/7zip/7zip-benchmark.test   1722.00 2189.00 27.1%
 test-suite...CFP2000/177.mesa/177.mesa.test    30.00   38.00  26.7%
 test-suite :: External/Nurbs/nurbs.test        44.00   49.00  11.4%
 test-suite...lications/sqlite3/sqlite3.test   115.00  128.00  11.3%
 test-suite...006/447.dealII/447.dealII.test   2715.00 3013.00 11.0%
 test-suite...ProxyApps-C++/CLAMR/CLAMR.test   237.00  261.00  10.1%
 test-suite...tions/lambda-0.1.3/lambda.test    40.00   44.00  10.0%
 test-suite...3.xalancbmk/483.xalancbmk.test   1366.00 1475.00  8.0%
 test-suite...abench/jpeg/jpeg-6a/cjpeg.test    13.00   14.00   7.7%
 test-suite...oxyApps-C++/miniFE/miniFE.test    43.00   46.00   7.0%
 test-suite...lications/ClamAV/clamscan.test   230.00  246.00   7.0%
 test-suite...006/450.soplex/450.soplex.test   284.00  299.00   5.3%
 test-suite...nsumer-jpeg/consumer-jpeg.test    21.00   22.00   4.8%
This commit is contained in:
Florian Hahn 2020-10-20 16:41:56 +01:00
parent 217c406c57
commit f50dd85440
2 changed files with 9 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
lib/Transforms/Scalar/DeadStoreElimination.cpp
View File

@ -2140,17 +2140,21 @@ struct DSEState {
continue;
}
// A memory terminator kills all preceeding MemoryDefs and all succeeding
// MemoryAccesses. We do not have to check it's users.
if (isMemTerminator(DefLoc, KillingI, UseInst)) {
LLVM_DEBUG(
dbgs()
<< " ... skipping, memterminator invalidates following accesses\n");
continue;
}
if (isNoopIntrinsic(cast<MemoryUseOrDef>(UseAccess)->getMemoryInst())) {
LLVM_DEBUG(dbgs() << " ... adding uses of intrinsic\n");
PushMemUses(UseAccess);
continue;
}
// A memory terminator kills all preceeding MemoryDefs and all succeeding
// MemoryAccesses. We do not have to check it's users.
if (isMemTerminator(DefLoc, KillingI, UseInst))
continue;
if (UseInst->mayThrow() && !isInvisibleToCallerBeforeRet(DefUO)) {
LLVM_DEBUG(dbgs() << " ... found throwing instruction\n");
Cache.KnownReads.insert(UseAccess);

2
test/Transforms/DeadStoreElimination/MSSA/lifetime.ll
View File

@ -84,8 +84,6 @@ define void @test4_lifetime_end_partial_loop() {
; CHECK-NEXT: [[A_2:%.*]] = getelementptr i8, i8* [[A_0]], i64 2
; CHECK-NEXT: call void @use(i8* [[A_1]])
; CHECK-NEXT: store i8 20, i8* [[A_2]], align 1
; CHECK-NEXT: store i8 10, i8* [[A_1]], align 1
; CHECK-NEXT: store i8 0, i8* [[A_0]], align 1
; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 2, i8* [[A_0]])
; CHECK-NEXT: [[IV_NEXT]] = add i8 [[IV]], 10
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i8 [[IV_NEXT]], 10