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[CSSPGO] Unblock optimizations with pseudo probe instrumentation part 2.

As a follow-up to D95982, this patch continues unblocking optimizations that are blocked by pseudu probe instrumention.

The optimizations unblocked are:
		- In-block load propagation.
		- In-block dead store elimination
		- Memory copy optimization that turns stores to consecutive memories into a memset.

These optimizations are local to a block, so they shouldn't affect the profile quality.

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D100075
This commit is contained in:
Hongtao Yu 2021-04-26 09:12:29 -07:00
parent d0dc7f2344
commit 7416a011e2
6 changed files with 69 additions and 8 deletions

View File

@ -532,7 +532,7 @@ Value *llvm::findAvailablePtrLoadStore(
// We must ignore debug info directives when counting (otherwise they
// would affect codegen).
Instruction *Inst = &*--ScanFrom;
if (isa<DbgInfoIntrinsic>(Inst))
if (Inst->isDebugOrPseudoInst())
continue;
// Restore ScanFrom to expected value in case next test succeeds
@ -620,7 +620,7 @@ Value *llvm::FindAvailableLoadedValue(LoadInst *Load, AAResults &AA,
SmallVector<Instruction *> MustNotAliasInsts;
for (Instruction &Inst : make_range(++Load->getReverseIterator(),
ScanBB->rend())) {
if (isa<DbgInfoIntrinsic>(&Inst))
if (Inst.isDebugOrPseudoInst())
continue;
if (MaxInstsToScan-- == 0)

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@ -1396,7 +1396,7 @@ Instruction *InstCombinerImpl::visitStoreInst(StoreInst &SI) {
--BBI;
// Don't count debug info directives, lest they affect codegen,
// and we skip pointer-to-pointer bitcasts, which are NOPs.
if (isa<DbgInfoIntrinsic>(BBI) ||
if (BBI->isDebugOrPseudoInst() ||
(isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy())) {
ScanInsts++;
continue;

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@ -399,6 +399,13 @@ Instruction *MemCpyOptPass::tryMergingIntoMemset(Instruction *StartInst,
}
}
// Calls that only access inaccessible memory do not block merging
// accessible stores.
if (auto *CB = dyn_cast<CallBase>(BI)) {
if (CB->onlyAccessesInaccessibleMemory())
continue;
}
if (!isa<StoreInst>(BI) && !isa<MemSetInst>(BI)) {
// If the instruction is readnone, ignore it, otherwise bail out. We
// don't even allow readonly here because we don't want something like:

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@ -202,7 +202,7 @@ static bool ProcessBlock(BasicBlock &BB, DominatorTree &DT, LoopInfo &LI,
if (!ProcessedBegin)
--I;
if (isa<DbgInfoIntrinsic>(Inst))
if (Inst->isDebugOrPseudoInst())
continue;
if (SinkInstruction(Inst, Stores, DT, LI, AA)) {

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@ -1,4 +1,4 @@
; RUN: opt -passes=instcombine -S < %s | FileCheck %s
; RUN: opt -passes=instcombine -available-load-scan-limit=2 -S < %s | FileCheck %s
%struct.nonbonded = type { [2 x %struct.CompAtom*], [2 x %struct.CompAtomExt*], [2 x %struct.CompAtom*], [2 x %class.Vector*], [2 x %class.Vector*], [2 x i32], %class.Vector, double*, double*, %class.ComputeNonbondedWorkArrays*, %class.Pairlists*, i32, i32, double, double, i32, i32, i32, i32 }
%struct.CompAtomExt = type { i32 }
@ -13,11 +13,11 @@
%class.ResizeArrayRaw.3 = type <{ %class.Vector*, i8*, i32, i32, i32, float, i32, [4 x i8] }>
%class.Pairlists = type { i16*, i32, i32 }
define dso_local void @merge(%struct.nonbonded* nocapture readonly %params) local_unnamed_addr align 2 {
;; Check the minPart4 and minPart assignments are merged.
; CHECK-LABEL: @merge(
; CHECK-COUNT-1: getelementptr inbounds %struct.nonbonded, %struct.nonbonded* %params, i64 0, i32 16
; CHECK-NOT: getelementptr inbounds %struct.nonbonded, %struct.nonbonded* %params, i64 0, i32 16
define dso_local void @_ZN20ComputeNonbondedUtil9calc_pairEP9nonbonded(%struct.nonbonded* nocapture readonly %params) local_unnamed_addr align 2 {
entry:
%savePairlists3 = getelementptr inbounds %struct.nonbonded, %struct.nonbonded* %params, i64 0, i32 11
%0 = load i32, i32* %savePairlists3, align 8
@ -58,7 +58,36 @@ if.else147: ; preds = %if.then138
ret void
}
declare dso_local void @_ZN9Pairlists8addIndexEv() align 2
define i32 @load(i32* nocapture %a, i32* nocapture %b) {
;; Check the last store is deleted.
; CHECK-LABEL: @load(
; CHECK-NEXT: %1 = getelementptr inbounds i32, i32* %a, i64 1
; CHECK-NEXT: %2 = load i32, i32* %1, align 8
; CHECK-NEXT: %3 = getelementptr inbounds i32, i32* %b, i64 1
; CHECK-NEXT: store i32 %2, i32* %3, align 8
; CHECK-NEXT: call void @llvm.pseudoprobe(i64 5116412291814990879, i64 1, i32 0, i64 -1)
; CHECK-NEXT: ret i32 %[[#]]
%1 = getelementptr inbounds i32, i32* %a, i32 1
%2 = load i32, i32* %1, align 8
%3 = getelementptr inbounds i32, i32* %b, i32 1
store i32 %2, i32* %3, align 8
%4 = getelementptr inbounds i32, i32* %b, i32 1
call void @llvm.pseudoprobe(i64 5116412291814990879, i64 1, i32 0, i64 -1)
%5 = load i32, i32* %4, align 8
ret i32 %5
}
define void @dse(i32* %p) {
;; Check the first store is deleted.
; CHECK-LABEL: @dse(
; CHECK-NEXT: call void @llvm.pseudoprobe(i64 5116412291814990879, i64 1, i32 0, i64 -1)
; CHECK-NEXT: store i32 0, i32* [[P:%.*]], align 4
; CHECK-NEXT: ret void
store i32 0, i32* %p
call void @llvm.pseudoprobe(i64 5116412291814990879, i64 1, i32 0, i64 -1)
store i32 0, i32* %p
ret void
}
; Function Attrs: inaccessiblememonly nounwind willreturn
declare void @llvm.pseudoprobe(i64, i64, i32, i64) #0

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@ -0,0 +1,25 @@
; RUN: opt < %s -memcpyopt -S | FileCheck %s
%struct.MV = type { i16, i16 }
define void @test(i32* nocapture %c) nounwind optsize {
; All the stores in this example should be merged into a single memset.
; CHECK-NOT: store i32 -1
; CHECK: call void @llvm.memset.p0i8.i64
store i32 -1, i32* %c, align 4
%1 = getelementptr inbounds i32, i32* %c, i32 1
store i32 -1, i32* %1, align 4
%2 = getelementptr inbounds i32, i32* %c, i32 2
store i32 -1, i32* %2, align 4
call void @llvm.pseudoprobe(i64 5116412291814990879, i64 1, i32 0, i64 -1)
%3 = getelementptr inbounds i32, i32* %c, i32 3
store i32 -1, i32* %3, align 4
%4 = getelementptr inbounds i32, i32* %c, i32 4
store i32 -1, i32* %4, align 4
ret void
}
; Function Attrs: inaccessiblememonly nounwind willreturn
declare void @llvm.pseudoprobe(i64, i64, i32, i64) #0
attributes #0 = { inaccessiblememonly nounwind willreturn }