| Message ID | 304a06e3-e037-6467-6606-d08a2d4d1ce1@e124511.cambridge.arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | aarch64: Fix costing of move to/from MOVEABLE_SYSREGS | expand |
Andrew Carlotti <andrew.carlotti@arm.com> writes: > This is necessary to prevent reload assuming that a direct FP->FPMR move > is valid. > > Bootstrapped and regression tested; ok for master? > > gcc/ChangeLog: > > * config/aarch64/aarch64.cc (aarch64_register_move_cost): > Increase costs involving MOVEABLE_SYSREGS. > > > diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc > index c03ca2c24ed702803989024193dae07155445978..73a555d61cfb4c150cb5a0e7b9d09f3075f0c0b4 100644 > --- a/gcc/config/aarch64/aarch64.cc > +++ b/gcc/config/aarch64/aarch64.cc > @@ -15500,6 +15500,12 @@ aarch64_register_move_cost (machine_mode mode, > reg_class_contents[FFR_REGS])) > return 80; > > + /* Moves to/from sysregs are expensive, and must go via GPR. */ > + if (from == MOVEABLE_SYSREGS) > + return 80 + aarch64_register_move_cost (mode, GENERAL_REGS, to); > + if (to == MOVEABLE_SYSREGS) > + return 80 + aarch64_register_move_cost (mode, from, GENERAL_REGS); > + LGTM. There's precedent for hard-coding a very large value (for FFR) and I agree that this case is similarly problematic. And it doesn't seem like a useful tuning parameter. OK if there are no objections before Thursday local time. Thanks, Richard > /* Moving between GPR and stack cost is the same as GP2GP. */ > if ((from == GENERAL_REGS && to == STACK_REG) > || (to == GENERAL_REGS && from == STACK_REG))
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc index c03ca2c24ed702803989024193dae07155445978..73a555d61cfb4c150cb5a0e7b9d09f3075f0c0b4 100644 --- a/gcc/config/aarch64/aarch64.cc +++ b/gcc/config/aarch64/aarch64.cc @@ -15500,6 +15500,12 @@ aarch64_register_move_cost (machine_mode mode, reg_class_contents[FFR_REGS])) return 80; + /* Moves to/from sysregs are expensive, and must go via GPR. */ + if (from == MOVEABLE_SYSREGS) + return 80 + aarch64_register_move_cost (mode, GENERAL_REGS, to); + if (to == MOVEABLE_SYSREGS) + return 80 + aarch64_register_move_cost (mode, from, GENERAL_REGS); + /* Moving between GPR and stack cost is the same as GP2GP. */ if ((from == GENERAL_REGS && to == STACK_REG) || (to == GENERAL_REGS && from == STACK_REG))