[X86] Review current scheduler classes to minimise need for InstRW overrides #36479
Description
| Bugzilla Link | 37131 |
| Version | trunk |
| OS | Windows NT |
| Depends On | #32204 #34956 #36074 #36259 #36272 #36278 #36279 |
| Blocks | #31672 #34896 |
| CC | @adibiagio,@legrosbuffle,@topperc,@rotateright |
Extended Description
Many models are making very poor use of the default scheduler classes, with many using InstrRW, resulting in cases such as:
1 - A default class isn't used at all, and all its instructions use InstrRW - we should be able to at least move some instructions to the default, or split the class to match as many instructions as possible across all targets.
2 - An instruction uses InstrRW but in fact matches the default class values (Bug #35548).
3 - Some targets just don't need to use some scheduler classes at all (Bug #35608).
This patch is to track possible splits to the classes that would help us move away from unnecessary InstRW usage and make the scheduler models more easily maintainable.