[llvm] r321138 - [memcpyopt] Teach memcpyopt to optimize across basic blocks
Reid Kleckner via llvm-commits
llvm-commits at lists.llvm.org
Thu Dec 28 10:27:20 PST 2017
I ended up reverting this, and posted a reduced test case for it in
https://llvm.org/PR35519. I think memdep needs some more work. I'm
concerned that memcpyopt (or maybe memdep) is sensitive to debug info.
On Sat, Dec 23, 2017 at 7:13 AM, Hans Wennborg <hans at chromium.org> wrote:
> This caused Chrome (on Mac) to crash on start-up: http://crbug.com/797267
>
> We don't seem to have a good analysis of the problem yet, but perhaps
> we should revert this before it bites others?
>
> In any case, this is a heads up that there might be a problem here.
>
> On Tue, Dec 19, 2017 at 5:36 PM, Dan Gohman via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Author: djg
> > Date: Tue Dec 19 17:36:25 2017
> > New Revision: 321138
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=321138&view=rev
> > Log:
> > [memcpyopt] Teach memcpyopt to optimize across basic blocks
> >
> > This teaches memcpyopt to make a non-local memdep query when a local
> query
> > indicates that the dependency is non-local. This notably allows it to
> > eliminate many more llvm.memcpy calls in common Rust code, often by
> 20-30%.
> >
> > This is r319482 and r319483, along with fixes for PR35519: fix the
> > optimization that merges stores into memsets to preserve cached memdep
> > info, and fix memdep's non-local caching strategy to not assume that
> larger
> > queries are always more conservative than smaller ones.
> >
> > Fixes PR28958 and PR35519.
> >
> > Differential Revision: https://reviews.llvm.org/D40802
> >
> > Added:
> > llvm/trunk/test/Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll
> > llvm/trunk/test/Transforms/MemCpyOpt/merge-into-memset.ll
> > llvm/trunk/test/Transforms/MemCpyOpt/mixed-sizes.ll
> > llvm/trunk/test/Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll
> > Modified:
> > llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h
> > llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
> > llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
> >
> > Modified: llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
> llvm/Analysis/MemoryDependenceAnalysis.h?rev=321138&r1=321137&r2=
> 321138&view=diff
> > ============================================================
> ==================
> > --- llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h
> (original)
> > +++ llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h Tue Dec
> 19 17:36:25 2017
> > @@ -407,6 +407,12 @@ public:
> > void getNonLocalPointerDependency(Instruction *QueryInst,
> > SmallVectorImpl<NonLocalDepResult>
> &Result);
> >
> > + /// Perform a dependency query specifically for QueryInst's access to
> Loc.
> > + /// The other comments for getNonLocalPointerDependency apply here as
> well.
> > + void getNonLocalPointerDependencyFrom(Instruction *QueryInst,
> > + const MemoryLocation &Loc, bool
> isLoad,
> > + SmallVectorImpl<NonLocalDepResult>
> &Result);
> > +
> > /// Removes an instruction from the dependence analysis, updating the
> > /// dependence of instructions that previously depended on it.
> > void removeInstruction(Instruction *InstToRemove);
> >
> > Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/
> MemoryDependenceAnalysis.cpp?rev=321138&r1=321137&r2=321138&view=diff
> > ============================================================
> ==================
> > --- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
> > +++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Tue Dec 19
> 17:36:25 2017
> > @@ -919,6 +919,14 @@ void MemoryDependenceResults::getNonLoca
> > Instruction *QueryInst, SmallVectorImpl<NonLocalDepResult>
> &Result) {
> > const MemoryLocation Loc = MemoryLocation::get(QueryInst);
> > bool isLoad = isa<LoadInst>(QueryInst);
> > + return getNonLocalPointerDependencyFrom(QueryInst, Loc, isLoad,
> Result);
> > +}
> > +
> > +void MemoryDependenceResults::getNonLocalPointerDependencyFrom(
> > + Instruction *QueryInst,
> > + const MemoryLocation &Loc,
> > + bool isLoad,
> > + SmallVectorImpl<NonLocalDepResult> &Result) {
> > BasicBlock *FromBB = QueryInst->getParent();
> > assert(FromBB);
> >
> > @@ -1118,21 +1126,15 @@ bool MemoryDependenceResults::getNonLoca
> > // If we already have a cache entry for this CacheKey, we may need to
> do some
> > // work to reconcile the cache entry and the current query.
> > if (!Pair.second) {
> > - if (CacheInfo->Size < Loc.Size) {
> > - // The query's Size is greater than the cached one. Throw out the
> > - // cached data and proceed with the query at the greater size.
> > + if (CacheInfo->Size != Loc.Size) {
> > + // The query's Size differs from the cached one. Throw out the
> > + // cached data and proceed with the query at the new size.
> > CacheInfo->Pair = BBSkipFirstBlockPair();
> > CacheInfo->Size = Loc.Size;
> > for (auto &Entry : CacheInfo->NonLocalDeps)
> > if (Instruction *Inst = Entry.getResult().getInst())
> > RemoveFromReverseMap(ReverseNonLocalPtrDeps, Inst, CacheKey);
> > CacheInfo->NonLocalDeps.clear();
> > - } else if (CacheInfo->Size > Loc.Size) {
> > - // This query's Size is less than the cached one. Conservatively
> restart
> > - // the query using the greater size.
> > - return getNonLocalPointerDepFromBB(
> > - QueryInst, Pointer, Loc.getWithNewSize(CacheInfo->Size),
> isLoad,
> > - StartBB, Result, Visited, SkipFirstBlock);
> > }
> >
> > // If the query's AATags are inconsistent with the cached one,
> >
> > Modified: llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> Transforms/Scalar/MemCpyOptimizer.cpp?rev=321138&r1=321137&r2=321138&
> view=diff
> > ============================================================
> ==================
> > --- llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp Tue Dec 19
> 17:36:25 2017
> > @@ -476,22 +476,33 @@ Instruction *MemCpyOptPass::tryMergingIn
> > Alignment = DL.getABITypeAlignment(EltType);
> > }
> >
> > - AMemSet =
> > - Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start,
> Alignment);
> > + // Remember the debug location.
> > + DebugLoc Loc;
> > + if (!Range.TheStores.empty())
> > + Loc = Range.TheStores[0]->getDebugLoc();
> >
> > DEBUG(dbgs() << "Replace stores:\n";
> > for (Instruction *SI : Range.TheStores)
> > - dbgs() << *SI << '\n';
> > - dbgs() << "With: " << *AMemSet << '\n');
> > -
> > - if (!Range.TheStores.empty())
> > - AMemSet->setDebugLoc(Range.TheStores[0]->getDebugLoc());
> > + dbgs() << *SI << '\n');
> >
> > // Zap all the stores.
> > for (Instruction *SI : Range.TheStores) {
> > MD->removeInstruction(SI);
> > SI->eraseFromParent();
> > }
> > +
> > + // Create the memset after removing the stores, so that if there
> any cached
> > + // non-local dependencies on the removed instructions in
> > + // MemoryDependenceAnalysis, the cache entries are updated to
> "dirty"
> > + // entries pointing below the memset, so subsequent queries include
> the
> > + // memset.
> > + AMemSet =
> > + Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start,
> Alignment);
> > + if (!Range.TheStores.empty())
> > + AMemSet->setDebugLoc(Loc);
> > +
> > + DEBUG(dbgs() << "With: " << *AMemSet << '\n');
> > +
> > ++NumMemSetInfer;
> > }
> >
> > @@ -1031,9 +1042,22 @@ bool MemCpyOptPass::processMemCpyMemCpyD
> > //
> > // NOTE: This is conservative, it will stop on any read from the
> source loc,
> > // not just the defining memcpy.
> > - MemDepResult SourceDep =
> > - MD->getPointerDependencyFrom(MemoryLocation::getForSource(MDep),
> false,
> > - M->getIterator(), M->getParent());
> > + MemoryLocation SourceLoc = MemoryLocation::getForSource(MDep);
> > + MemDepResult SourceDep = MD->getPointerDependencyFrom(SourceLoc,
> false,
> > +
> M->getIterator(), M->getParent());
> > +
> > + if (SourceDep.isNonLocal()) {
> > + SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
> > + MD->getNonLocalPointerDependencyFrom(M, SourceLoc,
> /*isLoad=*/false,
> > + NonLocalDepResults);
> > + if (NonLocalDepResults.size() == 1) {
> > + SourceDep = NonLocalDepResults[0].getResult();
> > + assert((!SourceDep.getInst() ||
> > + LookupDomTree().dominates(SourceDep.getInst(), M)) &&
> > + "when memdep returns exactly one result, it should
> dominate");
> > + }
> > + }
> > +
> > if (!SourceDep.isClobber() || SourceDep.getInst() != MDep)
> > return false;
> >
> > @@ -1235,6 +1259,18 @@ bool MemCpyOptPass::processMemCpy(MemCpy
> > MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(
> > SrcLoc, true, M->getIterator(), M->getParent());
> >
> > + if (SrcDepInfo.isNonLocal()) {
> > + SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
> > + MD->getNonLocalPointerDependencyFrom(M, SrcLoc, /*isLoad=*/true,
> > + NonLocalDepResults);
> > + if (NonLocalDepResults.size() == 1) {
> > + SrcDepInfo = NonLocalDepResults[0].getResult();
> > + assert((!SrcDepInfo.getInst() ||
> > + LookupDomTree().dominates(SrcDepInfo.getInst(), M)) &&
> > + "when memdep returns exactly one result, it should
> dominate");
> > + }
> > + }
> > +
> > if (SrcDepInfo.isClobber()) {
> > if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(SrcDepInfo.getInst()))
> > return processMemCpyMemCpyDependence(M, MDep);
> >
> > Added: llvm/trunk/test/Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll?rev=321138&view=auto
> > ============================================================
> ==================
> > --- llvm/trunk/test/Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll (added)
> > +++ llvm/trunk/test/Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll Tue
> Dec 19 17:36:25 2017
> > @@ -0,0 +1,48 @@
> > +; RUN: opt < %s -memcpyopt -S | FileCheck %s
> > +; Test memcpy-memcpy dependencies across invoke edges.
> > +
> > +; Test that memcpyopt works across the non-unwind edge of an invoke.
> > +
> > +define hidden void @test_normal(i8* noalias %dst, i8* %src) personality
> i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
> > +entry:
> > + %temp = alloca i8, i32 64
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64
> 64, i32 8, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull
> %src, i64 64, i32 8, i1 false)
> > + invoke void @invoke_me()
> > + to label %try.cont unwind label %lpad
> > +
> > +lpad:
> > + landingpad { i8*, i32 }
> > + catch i8* null
> > + ret void
> > +
> > +try.cont:
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %temp, i64 64, i32
> 8, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64
> 64, i32 8, i1 false)
> > + ret void
> > +}
> > +
> > +; Test that memcpyopt works across the unwind edge of an invoke.
> > +
> > +define hidden void @test_unwind(i8* noalias %dst, i8* %src) personality
> i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
> > +entry:
> > + %temp = alloca i8, i32 64
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64
> 64, i32 8, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull
> %src, i64 64, i32 8, i1 false)
> > + invoke void @invoke_me()
> > + to label %try.cont unwind label %lpad
> > +
> > +lpad:
> > + landingpad { i8*, i32 }
> > + catch i8* null
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %temp, i64 64, i32
> 8, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64
> 64, i32 8, i1 false)
> > + ret void
> > +
> > +try.cont:
> > + ret void
> > +}
> > +
> > +declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8*
> nocapture readonly, i64, i32, i1)
> > +declare i32 @__gxx_personality_v0(...)
> > +declare void @invoke_me() readnone
> >
> > Added: llvm/trunk/test/Transforms/MemCpyOpt/merge-into-memset.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> Transforms/MemCpyOpt/merge-into-memset.ll?rev=321138&view=auto
> > ============================================================
> ==================
> > --- llvm/trunk/test/Transforms/MemCpyOpt/merge-into-memset.ll (added)
> > +++ llvm/trunk/test/Transforms/MemCpyOpt/merge-into-memset.ll Tue Dec
> 19 17:36:25 2017
> > @@ -0,0 +1,45 @@
> > +; RUN: opt < %s -memcpyopt -S | FileCheck %s
> > +; Update cached non-local dependence information when merging stores
> into memset.
> > +
> > +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> > +
> > +; Don't delete the memcpy in %if.then, even though it depends on an
> instruction
> > +; which will be deleted.
> > +
> > +; CHECK-LABEL: @foo
> > +define void @foo(i1 %c, i8* %d, i8* %e, i8* %f) {
> > +entry:
> > + %tmp = alloca [50 x i8], align 8
> > + %tmp4 = bitcast [50 x i8]* %tmp to i8*
> > + %tmp1 = getelementptr inbounds i8, i8* %tmp4, i64 1
> > + call void @llvm.memset.p0i8.i64(i8* nonnull %d, i8 0, i64 10, i32 1,
> i1 false), !dbg !5
> > + store i8 0, i8* %tmp4, align 8, !dbg !5
> > +; CHECK: call void @llvm.memset.p0i8.i64(i8* nonnull %d, i8 0, i64 10,
> i32 1, i1 false), !dbg !5
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %tmp1, i8* nonnull
> %d, i64 10, i32 1, i1 false)
> > + br i1 %c, label %if.then, label %exit
> > +
> > +if.then:
> > +; CHECK: if.then:
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %f, i8* nonnull
> %tmp4, i64 30, i32 8, i1 false)
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %f, i8* nonnull %tmp4, i64
> 30, i32 8, i1 false)
> > + br label %exit
> > +
> > +exit:
> > + ret void
> > +}
> > +
> > +declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)
> > +declare void @llvm.memset.p0i8.i64(i8*, i8, i64, i32, i1)
> > +
> > +!llvm.dbg.cu = !{!0}
> > +!llvm.module.flags = !{!3, !4}
> > +
> > +!0 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !1,
> isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
> > +!1 = !DIFile(filename: "t.rs", directory: "/tmp")
> > +!2 = !{}
> > +!3 = !{i32 2, !"Dwarf Version", i32 4}
> > +!4 = !{i32 2, !"Debug Info Version", i32 3}
> > +!5 = !DILocation(line: 8, column: 5, scope: !6)
> > +!6 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 5,
> type: !7, isLocal: false, isDefinition: true, scopeLine: 5, flags:
> DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
> > +!7 = !DISubroutineType(types: !8)
> > +!8 = !{null}
> >
> > Added: llvm/trunk/test/Transforms/MemCpyOpt/mixed-sizes.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> Transforms/MemCpyOpt/mixed-sizes.ll?rev=321138&view=auto
> > ============================================================
> ==================
> > --- llvm/trunk/test/Transforms/MemCpyOpt/mixed-sizes.ll (added)
> > +++ llvm/trunk/test/Transforms/MemCpyOpt/mixed-sizes.ll Tue Dec 19
> 17:36:25 2017
> > @@ -0,0 +1,36 @@
> > +; RUN: opt < %s -memcpyopt -S | FileCheck %s
> > +; Handle memcpy-memcpy dependencies of differing sizes correctly.
> > +
> > +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> > +
> > +; Don't delete the second memcpy, even though there's an earlier
> > +; memcpy with a larger size from the same address.
> > +
> > +; CHECK-LABEL: @foo
> > +define i32 @foo(i1 %z) {
> > +entry:
> > + %a = alloca [10 x i32]
> > + %s = alloca [10 x i32]
> > + %0 = bitcast [10 x i32]* %a to i8*
> > + %1 = bitcast [10 x i32]* %s to i8*
> > + call void @llvm.memset.p0i8.i64(i8* nonnull %1, i8 0, i64 40, i32 16,
> i1 false)
> > + %arrayidx = getelementptr inbounds [10 x i32], [10 x i32]* %a, i64 0,
> i64 0
> > + store i32 1, i32* %arrayidx
> > + %scevgep = getelementptr [10 x i32], [10 x i32]* %s, i64 0, i64 1
> > + %scevgep7 = bitcast i32* %scevgep to i8*
> > + br i1 %z, label %for.body3.lr.ph, label %for.inc7.1
> > +
> > +for.body3.lr.ph: ; preds = %entry
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %scevgep7, i64
> 17179869180, i32 4, i1 false)
> > + br label %for.inc7.1
> > +
> > +for.inc7.1:
> > +; CHECK: for.inc7.1:
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %scevgep7, i64 4,
> i32 4, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %scevgep7,
> i64 4, i32 4, i1 false)
> > + %2 = load i32, i32* %arrayidx
> > + ret i32 %2
> > +}
> > +
> > +declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)
> > +declare void @llvm.memset.p0i8.i64(i8*, i8, i64, i32, i1)
> >
> > Added: llvm/trunk/test/Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll?rev=321138&view=auto
> > ============================================================
> ==================
> > --- llvm/trunk/test/Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll
> (added)
> > +++ llvm/trunk/test/Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll Tue
> Dec 19 17:36:25 2017
> > @@ -0,0 +1,114 @@
> > +; RUN: opt < %s -memcpyopt -S | FileCheck %s
> > +; Make sure memcpy-memcpy dependence is optimized across
> > +; basic blocks (conditional branches and invokes).
> > +
> > +%struct.s = type { i32, i32 }
> > +
> > + at s_foo = private unnamed_addr constant %struct.s { i32 1, i32 2 },
> align 4
> > + at s_baz = private unnamed_addr constant %struct.s { i32 1, i32 2 },
> align 4
> > + at i = external constant i8*
> > +
> > +declare void @qux()
> > +declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8*
> nocapture readonly, i64, i32, i1)
> > +declare void @__cxa_throw(i8*, i8*, i8*)
> > +declare i32 @__gxx_personality_v0(...)
> > +declare i8* @__cxa_begin_catch(i8*)
> > +
> > +; A simple partial redundancy. Test that the second memcpy is optimized
> > +; to copy directly from the original source rather than from the
> temporary.
> > +
> > +; CHECK-LABEL: @wobble
> > +define void @wobble(i8* noalias %dst, i8* %src, i1 %some_condition) {
> > +bb:
> > + %temp = alloca i8, i32 64
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64
> 64, i32 8, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull
> %src, i64 64, i32 8, i1 false)
> > + br i1 %some_condition, label %more, label %out
> > +
> > +out:
> > + call void @qux()
> > + unreachable
> > +
> > +more:
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %temp, i64 64, i32
> 8, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64
> 64, i32 8, i1 false)
> > + ret void
> > +}
> > +
> > +; A CFG triangle with a partial redundancy targeting an alloca. Test
> that the
> > +; memcpy inside the triangle is optimized to copy directly from the
> original
> > +; source rather than from the temporary.
> > +
> > +; CHECK-LABEL: @foo
> > +define i32 @foo(i1 %t3) {
> > +bb:
> > + %s = alloca %struct.s, align 4
> > + %t = alloca %struct.s, align 4
> > + %s1 = bitcast %struct.s* %s to i8*
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s1, i8* bitcast (%struct.s*
> @s_foo to i8*), i64 8, i32 4, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s1, i8* bitcast
> (%struct.s* @s_foo to i8*), i64 8, i32 4, i1 false)
> > + br i1 %t3, label %bb4, label %bb7
> > +
> > +bb4: ; preds = %bb
> > + %t5 = bitcast %struct.s* %t to i8*
> > + %s6 = bitcast %struct.s* %s to i8*
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t5, i8* %s6, i64 8, i32 4,
> i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t5, i8* bitcast
> (%struct.s* @s_foo to i8*), i64 8, i32 4, i1 false)
> > + br label %bb7
> > +
> > +bb7: ; preds = %bb4, %bb
> > + %t8 = getelementptr %struct.s, %struct.s* %t, i32 0, i32 0
> > + %t9 = load i32, i32* %t8, align 4
> > + %t10 = getelementptr %struct.s, %struct.s* %t, i32 0, i32 1
> > + %t11 = load i32, i32* %t10, align 4
> > + %t12 = add i32 %t9, %t11
> > + ret i32 %t12
> > +}
> > +
> > +; A CFG diamond with an invoke on one side, and a partially redundant
> memcpy
> > +; into an alloca on the other. Test that the memcpy inside the diamond
> is
> > +; optimized to copy ; directly from the original source rather than
> from the
> > +; temporary. This more complex test represents a relatively common usage
> > +; pattern.
> > +
> > +; CHECK-LABEL: @baz
> > +define i32 @baz(i1 %t5) personality i8* bitcast (i32 (...)*
> @__gxx_personality_v0 to i8*) {
> > +bb:
> > + %s = alloca %struct.s, align 4
> > + %t = alloca %struct.s, align 4
> > + %s3 = bitcast %struct.s* %s to i8*
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s3, i8* bitcast (%struct.s*
> @s_baz to i8*), i64 8, i32 4, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s3, i8* bitcast
> (%struct.s* @s_baz to i8*), i64 8, i32 4, i1 false)
> > + br i1 %t5, label %bb6, label %bb22
> > +
> > +bb6: ; preds = %bb
> > + invoke void @__cxa_throw(i8* null, i8* bitcast (i8** @i to i8*), i8*
> null)
> > + to label %bb25 unwind label %bb9
> > +
> > +bb9: ; preds = %bb6
> > + %t10 = landingpad { i8*, i32 }
> > + catch i8* null
> > + br label %bb13
> > +
> > +bb13: ; preds = %bb9
> > + %t15 = call i8* @__cxa_begin_catch(i8* null)
> > + br label %bb23
> > +
> > +bb22: ; preds = %bb
> > + %t23 = bitcast %struct.s* %t to i8*
> > + %s24 = bitcast %struct.s* %s to i8*
> > + call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t23, i8* %s24, i64 8, i32
> 4, i1 false)
> > +; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t23, i8* bitcast
> (%struct.s* @s_baz to i8*), i64 8, i32 4, i1 false)
> > + br label %bb23
> > +
> > +bb23: ; preds = %bb22, %bb13
> > + %t17 = getelementptr inbounds %struct.s, %struct.s* %t, i32 0, i32 0
> > + %t18 = load i32, i32* %t17, align 4
> > + %t19 = getelementptr inbounds %struct.s, %struct.s* %t, i32 0, i32 1
> > + %t20 = load i32, i32* %t19, align 4
> > + %t21 = add nsw i32 %t18, %t20
> > + ret i32 %t21
> > +
> > +bb25: ; preds = %bb6
> > + unreachable
> > +}
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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