Jeff Law <l...@redhat.com> writes: > The mips64vr-elf target will fail building newlib, particularly the > mips16 newlib as we emit bogus assembly code. > > In particular the compiler will emit something like > > lwu $2,0($sp) > > That's invalid in mips16 mode AFAICT. > > That's emitted by the extendsidi pattern. It's a case where the operand > predicates are looser that the constraints. The code we get out of > reload is fine, but hard register propagation substitutes sp for a > (valid mips16) hard register that as the same value. Since hard > register propagation tests predicates, not constraints, the substitution > is successful and the bogus code is generated.
Isn't that the bug though? Post-reload passes must test the constraints as well as the predicates, to make sure that the change aligns with one of the available alternatives. Adding code to do that to individual MIPS patterns feels like a hack to me. The pass should be doing it itself. Thanks, Richard
