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Add optimization "X & 1 == 1" to "X & 1" (#61412) #62818

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merged 13 commits into from
Mar 21, 2022
Merged

Add optimization "X & 1 == 1" to "X & 1" (#61412) #62818

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b84813f
Add optimization "X & 1 == 1" to "X & 1" (#61412)
SkiFoD Dec 14, 2021
3fc4ee3
Moved the optimization to the morph phase (#61412)
SkiFoD Dec 16, 2021
b1d57dc
Done in post-order (#61412)
SkiFoD Dec 16, 2021
9e7d39a
Moved the optimization into fgOptimizeEqualityComparisonWithConst (#6…
SkiFoD Dec 16, 2021
232500b
Some corrections due the comments (#61412)
SkiFoD Dec 16, 2021
4e199b4
Fix of the picture (#61412)
SkiFoD Dec 17, 2021
4e33287
Add optNarrowTree use (#61412)
SkiFoD Dec 22, 2021
9011df3
Change narrowing to the type check (#61412)
SkiFoD Dec 24, 2021
45ebaa4
Fix regressions (#61412)
SkiFoD Dec 27, 2021
0bf5965
Moved the optimization to the lowering phase (#61412)
SkiFoD Jan 10, 2022
f62c64b
Reverted Morph changes (#61412)
SkiFoD Jan 11, 2022
f64a8ac
Moved the optimization into OptimizeConstCompare method (#61412)
SkiFoD Jan 12, 2022
175bac2
Add GT_EQ check(#61412)
SkiFoD Jan 18, 2022
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19 changes: 19 additions & 0 deletions src/coreclr/jit/lower.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2925,6 +2925,25 @@ GenTree* Lowering::OptimizeConstCompare(GenTree* cmp)

if (op2Value != 0)
{
// Optimizes (X & 1) == 1 to (X & 1)
// The compiler requires jumps to have relop operands, so we do not fold that case.
LIR::Use cmpUse;
if ((op2Value == 1) && cmp->OperIs(GT_EQ))
{
if (andOp2->IsIntegralConst(1) && (genActualType(op1) == cmp->TypeGet()) &&
BlockRange().TryGetUse(cmp, &cmpUse) && !cmpUse.User()->OperIs(GT_JTRUE))
{
GenTree* next = cmp->gtNext;

cmpUse.ReplaceWith(op1);

BlockRange().Remove(cmp->gtGetOp2());
BlockRange().Remove(cmp);

return next;
}
}

//
// If we don't have a 0 compare we can get one by transforming ((x AND mask) EQ|NE mask)
// into ((x AND mask) NE|EQ 0) when mask is a single bit.
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