Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

unblock cloning of loops where the header is a try begin #108604

Merged
merged 6 commits into from
Oct 15, 2024
Merged

unblock cloning of loops where the header is a try begin #108604

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
fd23d60
unblock cloning of loops where the header is a try begin
AndyAyersMS Oct 7, 2024
0859c7c
Merge branch 'main' into EnableCloningWhenLoopHeaderIsTryRegionStart
AndyAyersMS Oct 14, 2024
6dc3a90
Merge branch 'main' into EnableCloningWhenLoopHeaderIsTryRegionStart
AndyAyersMS Oct 14, 2024
e2cdcd0
Merge remote-tracking branch 'origin/EnableCloningWhenLoopHeaderIsTry…
AndyAyersMS Oct 15, 2024
b7320bd
review feedback
AndyAyersMS Oct 15, 2024
78812e6
format
AndyAyersMS Oct 15, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 2 additions & 2 deletions src/coreclr/jit/flowgraph.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5964,9 +5964,9 @@ bool FlowGraphNaturalLoop::CanDuplicate(INDEBUG(const char** reason))

Compiler* comp = m_dfsTree->GetCompiler();
BasicBlockVisit result = VisitLoopBlocks([=](BasicBlock* block) {
if (comp->bbIsTryBeg(block))
if (!BasicBlock::sameEHRegion(block, GetHeader()))
{
INDEBUG(*reason = "Loop has a `try` begin");
INDEBUG(*reason = "Loop not entirely within one EH region");
return BasicBlockVisit::Abort;
}

Expand Down
1 change: 0 additions & 1 deletion src/coreclr/jit/loopcloning.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1929,7 +1929,6 @@ bool Compiler::optIsLoopClonable(FlowGraphNaturalLoop* loop, LoopCloneContext* c
loop->GetIndex());
return false;
}

assert(!requireIterable || !lvaVarAddrExposed(iterInfo->IterVar));

if (requireIterable)
Expand Down
45 changes: 36 additions & 9 deletions src/coreclr/jit/optimizer.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2866,15 +2866,33 @@ bool Compiler::optCreatePreheader(FlowGraphNaturalLoop* loop)
{
BasicBlock* header = loop->GetHeader();

// If the header is already a try entry then we need to keep it as such
// since blocks from within the loop will be jumping back to it after we're
// done. Thus, in that case we insert the preheader in the enclosing try
// region.
unsigned headerEHRegion = header->hasTryIndex() ? header->getTryIndex() : EHblkDsc::NO_ENCLOSING_INDEX;
unsigned preheaderEHRegion = headerEHRegion;
if ((headerEHRegion != EHblkDsc::NO_ENCLOSING_INDEX) && bbIsTryBeg(header))
// If all loop backedges sources are within the same try region as the loop header,
// then the preheader can be in the same try region as the header.
//
// Otherwise the preheader must be in the enclosing try region.
//
unsigned preheaderEHRegion = EHblkDsc::NO_ENCLOSING_INDEX;
bool inSameRegionAsHeader = true;
if (header->hasTryIndex())
{
preheaderEHRegion = ehTrueEnclosingTryIndexIL(headerEHRegion);
preheaderEHRegion = header->getTryIndex();
for (FlowEdge* backEdge : loop->BackEdges())
{
BasicBlock* const backedgeSource = backEdge->getSourceBlock();
if (!bbInTryRegions(preheaderEHRegion, backedgeSource))
{
if (backedgeSource->hasTryIndex())
{
preheaderEHRegion = backedgeSource->getTryIndex();
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Previously we were using ehTrueEnclosingTryIndexIL here, but not anymore. Was it unnecessary?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

No, it was arguably better.

If there is a backedge source in a non-contained EH region we should use the true enclosing region of the header to vet any existing preheader, rather than a region based on the backedge source.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Updated. No diffs (locally, x64) from the previous version.

}
else
{
preheaderEHRegion = EHblkDsc::NO_ENCLOSING_INDEX;
}
inSameRegionAsHeader = false;
break;
}
}
}

if (!bbIsHandlerBeg(header) && (loop->EntryEdges().size() == 1))
Expand All @@ -2893,7 +2911,16 @@ bool Compiler::optCreatePreheader(FlowGraphNaturalLoop* loop)

BasicBlock* preheader = fgNewBBbefore(BBJ_ALWAYS, header, false);
preheader->SetFlags(BBF_INTERNAL);
fgSetEHRegionForNewPreheaderOrExit(preheader);

if (inSameRegionAsHeader)
{
fgExtendEHRegionBefore(header);
}
else
{
fgSetEHRegionForNewPreheaderOrExit(preheader);
}

preheader->bbCodeOffs = header->bbCodeOffs;

JITDUMP("Created new preheader " FMT_BB " for " FMT_LP "\n", preheader->bbNum, loop->GetIndex());
Expand Down
Loading