OptimizeInstruction: Optimize any boolean & (No overlap with boolean's LSB) ==> 0 #7505
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kripken
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Apr 18, 2025
kripken
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Apr 23, 2025
kripken
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kripken
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kripken
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Co-authored-by: Alon Zakai <[email protected]>
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After updating all you suggested, I've fuzzing for about 20 minutes; and all is well. |
kripken
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May 1, 2025
Comment on lines
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| using namespace Abstract; | ||
| using namespace Match; | ||
|
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Suggested change
| using namespace Abstract; | |
| using namespace Match; |
I think the current version does not use Abstract or Match?
| // Check left's max bits and right is constant. | ||
| auto leftMaxBits = Bits::getMaxBits(left, this); | ||
| uint64_t maskLeft; | ||
| if (leftMaxBits == 64) { |
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This would be 32 for a 32-bit operation.
Suggested change
| if (leftMaxBits == 64) { | |
| if (leftMaxBits == left->type.getByteSize() * 8) { |
| uint64_t maskLeft; | ||
| if (leftMaxBits == 64) { | ||
| // If we know nothing useful about the bits on the left, | ||
| // we can not optimize. |
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Suggested change
| // we can not optimize. | |
| // we cannot optimize. |
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There are so many rules for
and, but we still cannot optimize the following one:to zero.
Adding rule for
add:any boolean & (No overlap with boolean's LSB) ==> 0Fixes: #7481