[FPBuiltinFnSelection] Fold fdiv-by-exact-reciprocal-constant to fmul - #22948
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[FPBuiltinFnSelection] Fold fdiv-by-exact-reciprocal-constant to fmul#22948bader wants to merge 1 commit into
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llvm.fpbuiltin.fdiv hides the division from InstCombine's foldFDivConstantDivisor until this pass lowers it to a real fdiv late in the pipeline, so InstCombine never gets a second look. Replicate the exact-reciprocal case of that fold here so X / C becomes X * (1/C) whenever C has an exact FP inverse.
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@jcranmer-intel, friendly reminder - I'm waiting your feedback on this PR. |
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llvm.fpbuiltin.fdiv hides the division from InstCombine's
foldFDivConstantDivisor until this pass lowers it to a real fdiv late
in the pipeline, so InstCombine never gets a second look. Replicate
the exact-reciprocal case of that fold here so X / C becomes X * (1/C)
whenever C has an exact FP inverse.
JIRA: CMPLRLLVM-77622