llvm-project

03123695 - [GlobalISel] Defer RegBankSelect operand mapper creation (#196985)

[GlobalISel] Defer RegBankSelect operand mapper creation (#196985) RegBankSelect::applyMapping constructs an OperandsMapper before applying repairs. Default mappings that only need Reassign repairs only update the register bank and do not create replacement operands, so the generic applyDefaultMapping path has no rewriting work to do in that case. Defer OperandsMapper creation until an Insert repair actually needs new virtual registers. If no mapper was needed for a default mapping, return after applying the repairs. CTMark geomean -0.23% improvement on aarch64-O0-g. https://llvm-compile-time-tracker.com/compare.php?from=ed50ea52004259af958bb3e5636268342c49ee62&to=1a4730426e14969626cad43c6b06e93bde707bd1&stat=instructions%3Au Assisted-by: Codex