spriv-opt: Adding a rule to merge select-binaryop #6456
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It seems that things like `(a ? 1u : 0u) == 1u` are surprisingly prevalent. When the select results in constants and the comparison is constant, we can merge the result directly into the select. The following cases have been added: ``` ((a ? C0 : C1) == C2) = ((a ? (C0 == C2) : (C1 == C2)) ((a ? C0 : C1) != C2) = ((a ? (C0 != C2) : (C1 != C2)) ((a ? C0 : C1) < C2) = ((a ? (C0 < C2) : (C1 < C2)) ((a ? C0 : C1) <= C2) = ((a ? (C0 <= C2) : (C1 <= C2)) ((a ? C0 : C1) > C2) = ((a ? (C0 > C2) : (C1 > C2)) ((a ? C0 : C1) >= C2) = ((a ? (C0 >= C2) : (C1 >= C2)) ((a ? C0 : C1) || C2) = ((a ? (C0 || C2) : (C1 || C2)) ((a ? C0 : C1) && C2) = ((a ? (C0 && C2) : (C1 && C2)) ``` This further opens the door to further collapses like: `(a ? true : false) = a`
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Updated review and description. |
``` ((a ? C0 : C1) + C2) = ((a ? (C0 + C2) : (C1 + C2)) ((a ? C0 : C1) - C2) = ((a ? (C0 - C2) : (C1 - C2)) ((a ? C0 : C1) * C2) = ((a ? (C0 * C2) : (C1 * C2)) ((a ? C0 : C1) / C2) = ((a ? (C0 / C2) : (C1 / C2)) ((a ? C0 : C1) >> C2) = ((a ? (C0 >> C2) : (C1 >> C2)) ((a ? C0 : C1) << C2) = ((a ? (C0 << C2) : (C1 << C2)) ((a ? C0 : C1) ^ C2) = ((a ? (C0 ^ C2) : (C1 ^ C2)) ((a ? C0 : C1) | C2) = ((a ? (C0 | C2) : (C1 | C2)) ((a ? C0 : C1) & C2) = ((a ? (C0 & C2) : (C1 & C2)) ``` Also sprinkled a few tests which switch lhs and rhs for the op being folded.
alister-chowdhury
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It seems that things like
(a ? 1u : 0u) == 1uare surprisingly prevalent.When the select results are constants and a binary op is constant, we can merge the result directly into the select.
The following cases have been added:
This further opens the door to further collapses like:
(a ? true : false) = a