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JIT: Improve BBJ_COND to BBJ_ALWAYS conversion in fgUpdateFlowGraph #97681

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amanasifkhalid wants to merge 4 commits into from
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JIT: Improve BBJ_COND to BBJ_ALWAYS conversion in fgUpdateFlowGraph #97681

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b65b966
Improve BBJ_COND to BBJ_ALWAYS conversion
amanasifkhalid Jan 30, 2024
9f3ac60
Remove unrelated change
amanasifkhalid Jan 30, 2024
cc8499c
Revert some small changes
amanasifkhalid Jan 30, 2024
d801192
Merge branch 'main' into opt-cond-to-uncond
amanasifkhalid Jan 30, 2024
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21 changes: 20 additions & 1 deletion src/coreclr/jit/fgopt.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4834,7 +4834,26 @@ bool Compiler::fgUpdateFlowGraph(bool doTailDuplication /* = false */, bool isPh
{
bDest = block->GetTrueTarget();
bFalseDest = block->GetFalseTarget();
if (bDest == bFalseDest)

if (bFalseDest->KindIs(BBJ_ALWAYS) && bFalseDest->TargetIs(bDest) && bFalseDest->isEmpty())
{
// Optimize block -> bFalseDest -> bDest into a BBJ_ALWAYS
block->SetFalseTarget(bDest);
fgAddRefPred(bDest, block, fgRemoveRefPred(bFalseDest, block));

// We will convert block to BBJ_ALWAYS, so no need to keep bFalseDest up to date
}
else if (bDest->KindIs(BBJ_ALWAYS) && bDest->TargetIs(bFalseDest) && bDest->isEmpty())
{
// Optimize block -> bDest -> bFalseDest into a BBJ_ALWAYS
block->SetTrueTarget(bFalseDest);
fgAddRefPred(bFalseDest, block, fgRemoveRefPred(bDest, block));

// We will continue to use bDest, so ensure it is up to date
bDest = bFalseDest;
}

if (block->FalseTargetIs(bDest))
{
fgRemoveConditionalJump(block);
assert(block->KindIs(BBJ_ALWAYS));
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