search for: compositeindices

Does anyone know exactly what ComposerIndices in Target.td is all about? I see just one place where it's used in X86 but it's not clear from the comments in Target.td and it's one usage, exactly what this feature is about. Tia. Reed

All, I've been trying to simplify the way LLVM models sub-register relationships a bit, and the X86 sub_ss and sub_sd sub-register indices are getting in the way. I want to get rid of them. These sub-registers are special, they are only mentioned here: let CompositeIndices = [(sub_ss), (sub_sd)] in { def XMM0: Register<"xmm0">, DwarfRegNum<[17, 21, 21]>; def XMM1: Register<"xmm1">, DwarfRegNum<[18, 22, 22]>; ... This secret syntax means that the indexes are idempotent: getSubReg(YMM0, sub_ss) --> XMM0 getSubR...

Jakob Stoklund Olesen <jolesen at apple.com> writes: > These sub-registers are special, they are only mentioned here: > > let CompositeIndices = [(sub_ss), (sub_sd)] in { > def XMM0: Register<"xmm0">, DwarfRegNum<[17, 21, 21]>; > def XMM1: Register<"xmm1">, DwarfRegNum<[18, 22, 22]>; > ... I'm confused. Below you note that they are used in patterns, so they are certainly men...