[PATCH] D41389: [WIP][InstCombine] Missed optimization in math expression: squashing sin(asin), cos(acos)

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

> are not erased after transform, however %call instruction is never used.

asin can set errno, which is a side-effect.  For "fast" calls we should probably treat them as dead anyway (in llvm::isMathLibCallNoop), but the issue generally doesn't come up because clang (incorrectly) marks math library calls readnone in fast-math mode.


https://reviews.llvm.org/D41389