Avoid CMOV with CFeq #2571
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Avoid CMOV with CFeq #2571
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TheNumbat
reviewed
May 14, 2024
TheNumbat
approved these changes
May 14, 2024
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Improve code generation for
Icselwhen the condition is float equality. This condition is not directly expressible as a CMOV mnemonic. To work around it, the compiler emits a jump instruction (to correctly handle the special case of Nan argument), defeating the purpose ofCMOV. This PR adds an ad-hoc pattern duringSelectionto detect this case, negate the condition and swap the arguments ofCMOV.Added a test to exercise this special case. I'm not adding any assembly grepping, because it's too fragile.