[llvm] [SystemZ] Add a SystemZ specific pre-RA scheduling strategy. (PR #135076)

[Jonas Paulsson via llvm-commits]

JonPsson1 wrote:

@uweigand regarding compile time (per pass as reported by -ftime-report):

- zig.bc: slightly worse but still relatively fast: 2.2% vs 1.7%.

- llvm test-suite build:
SystemZPreRASchedStrategy: Average: 0.98%, worst: 26.5%.
GenericScheduler: Average: 0.88%, worst: 25%.

So far no compile time explosions seen. One speedup that might be worth trying (in initialize()) would be to find the live-in regs by testing regs touched in the region only (as opposed to testing all of them). But since there are no known cases of this being significantly slow, maybe that can wait, or?



https://github.com/llvm/llvm-project/pull/135076