Tobias Stadler 2d9b6a01c7 [GlobalISel][AArch64] AArch64O0PreLegalizerCombiner: Disable fixed-point iteration (#94291) ...

This adds an option to CombinerInfo to limit the number of iterations in the
Combiner. This option is then used to disable fixed-point iteration for the
AArch64O0PreLegalizerCombiner. The combines there are simple enough that
code quality impact should be minimal with the current heuristics
(instructions are processed from top to bottom of the basic block,
new/changed instructions are added back to the worklist). Test changes
are due to some instructions not being DCE'd, which has no actual impact
because InstructionSelect performs DCE as well.

AArch64 CTMark O0:
-0.9% geomean compile-time (instruction count)
no change in size..text for any of the benchmarks

2024-06-14 17:51:09 +02:00

7.2 KiB

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