llvm-project

e6ef6b94 - [RegisterCoalescer] Update undef flags inside bundles (#227615)

[RegisterCoalescer] Update undef flags inside bundles (#227615) When joining makes an earlier subregister def a partial redefinition, JoinVals::pruneValues removes its undef flag. It only looked at the instruction returned by getInstructionFromIndex, which for a bundle is the BUNDLE header, so the def inside the bundle kept a stale undef flag that disagreed with the header. Update all operands in the bundle. Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>