llvm-project

35f1e158 - Greedy: Make trySplitAroundHintReg try to match hints with subreg copies

Greedy: Make trySplitAroundHintReg try to match hints with subreg copies This is essentially the same patch as 116ca9522e89f1e4e02676b5bbe505e80c4d4933; when trying to match a physreg hint, try to find a compatible physreg if there is a subregister copy. This has the slight difference of using getSubReg on the hint instead of getMatchingSuperReg (the other use should also use getSubReg instead, it's faster). At the moment this turns out to have very little effect. The adjacent code needs better handling of subregisters, so continue adding this piecemeal. The X86 test shows a net reduction in real instructions, plus a few new kills.