[llvm] r321138 - [memcpyopt] Teach memcpyopt to optimize across basic blocks
Michael Kruse via llvm-commits
llvm-commits at lists.llvm.org
Sat Dec 23 08:01:14 PST 2017
This also caused a miscompile with Polly. Polly added !noalias and
!alias.scope annotation to memcpy calls. I could not find any
reference to define to which of the pointers (source/dest) the
annotations should apply, so I treated it to be undefined and made
Polly stop adding such annotations. It had an effect on
MemoryDependenceAnalysis used by MemCpyOpt.
I don't know whether this is related, but might be a start to look for
the problem.
Michael
2017-12-23 16:13 GMT+01:00 Hans Wennborg via llvm-commits
<llvm-commits at lists.llvm.org>:
> 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
>> +}
>>
>>
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