| Message ID | 87d2atnsne.fsf@e105548-lin.cambridge.arm.com |
|---|---|
| State | New |
| Headers | show |
On 09/18/14 04:13, Richard Sandiford wrote: > combine.c:subst should refuse to substitute a hard register > into a subreg if the new subreg would not be simplified to a > simple hard register, since the result would have to be reloaded. > This is more for optimisation than correctness, since in theory > the RA should be able to fix up any unsimplified subregs. > > > gcc/ > * combine.c (subst): Use simplify_subreg_regno rather than > REG_CANNOT_CHANGE_MODE_P to detect invalid mode changes. OK independent of other changes. jeff
Index: gcc/combine.c =================================================================== --- gcc/combine.c 2014-09-15 10:00:17.545330404 +0100 +++ gcc/combine.c 2014-09-15 10:00:17.545330404 +0100 @@ -5121,15 +5121,13 @@ #define COMBINE_RTX_EQUAL_P(X,Y) \ ) return gen_rtx_CLOBBER (VOIDmode, const0_rtx); -#ifdef CANNOT_CHANGE_MODE_CLASS if (code == SUBREG && REG_P (to) && REGNO (to) < FIRST_PSEUDO_REGISTER - && REG_CANNOT_CHANGE_MODE_P (REGNO (to), - GET_MODE (to), - GET_MODE (x))) + && simplify_subreg_regno (REGNO (to), GET_MODE (to), + SUBREG_BYTE (x), + GET_MODE (x)) < 0) return gen_rtx_CLOBBER (VOIDmode, const0_rtx); -#endif new_rtx = (unique_copy && n_occurrences ? copy_rtx (to) : to); n_occurrences++;