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Revert r319482 and r319483 "[memcpyopt] Teach memcpyopt to optimize across basic blocks" 

This caused PR35519.

> [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%.
>
> Fixes PR28958.
>
> Differential Revision: https://reviews.llvm.org/D38374
>

> [memcpyopt] Commit file missed in r319482.
>
> This change was meant to be included with r319482 but was accidentally
> omitted.

llvm-svn: 319873
This commit is contained in:
Hans Wennborg 2017-12-06 01:47:55 +00:00
parent a149c1a517
commit 146a9c3e51
5 changed files with 3 additions and 204 deletions
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6
llvm/include/llvm/Analysis/MemoryDependenceAnalysis.h
View File

@ -407,12 +407,6 @@ 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);

8
llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
View File

@ -917,14 +917,6 @@ void MemoryDependenceResults::getNonLocalPointerDependency(
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);

31
llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
View File

@ -1031,22 +1031,9 @@ bool MemCpyOptPass::processMemCpyMemCpyDependence(MemCpyInst *M,
//
// NOTE: This is conservative, it will stop on any read from the source loc,
// not just the defining memcpy.
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");
}
}
MemDepResult SourceDep =
MD->getPointerDependencyFrom(MemoryLocation::getForSource(MDep), false,
M->getIterator(), M->getParent());
if (!SourceDep.isClobber() || SourceDep.getInst() != MDep)
return false;
@ -1248,18 +1235,6 @@ bool MemCpyOptPass::processMemCpy(MemCpyInst *M) {
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);

48
llvm/test/Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll
View File

@ -1,48 +0,0 @@
; 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

114
llvm/test/Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll
View File

@ -1,114 +0,0 @@
; 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 }
@s_foo = private unnamed_addr constant %struct.s { i32 1, i32 2 }, align 4
@s_baz = private unnamed_addr constant %struct.s { i32 1, i32 2 }, align 4
@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
}