llvm-project

01955119 - [InstCombine] Fix profile metadata propagation in InstCombine select folding (#179743)

[InstCombine] Fix profile metadata propagation in InstCombine select folding (#179743) Propagate profile metadata when canonicalizing SPF and drop it when folding select instructions with logical AND/OR conditions. This fixes profile verification failures in Transforms/InstCombine/select-and-or.ll. 1. Select Pattern Factor (SPF) Canonicalization When canonicalizing SPF patterns (like umax/umin), InstCombine transforms sequences like select i1 %cond,(select i1 %cmp, %x, %y), %z into intrinsic calls wrapped in a new select. The new outer select directly replaces the original select instruction, and its condition (%cond) remains structurally identical. Because the condition and its evaluated true/false semantics are unchanged, it is ok to copy the original !prof branch weight metadata to the newly created select. 2. Logical Boolean Folds (foldSelectOfBools) For logical boolean folds (e.g., transforming select (~a | c), a, b into select a, (select c, true, b), false), InstCombine restructures complex conditions into nested selects. In most cases, it is challenging to infer what the profile weights should be for the new select instructions. For a couple of places where should be able to infer profile weights, I've left a TODO to follow up.