| Message ID | 87wpg41zet.fsf@e105548-lin.cambridge.arm.com |
|---|---|
| State | New |
| Headers | show |
On 11/15/2016 09:27 AM, Richard Sandiford wrote: > local_cprop_find_used_regs punted on all multiword registers, > with the comment: > > /* Setting a subreg of a register larger than word_mode leaves > the non-written words unchanged. */ > > But this only applies if the outer mode is smaller than the > inner mode. If they're the same size then writes to the subreg > are a normal full update. > > This patch uses df_read_modify_subreg_p instead. A later patch > adds more uses of the same routine, but this part had a (positive) > effect on code generation for the testsuite whereas the others > seemed to be simple clean-ups. > > Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install? > > Thanks, > Richard > > > [ This patch is part of the SVE series posted here: > https://gcc.gnu.org/ml/gcc/2016-11/msg00030.html ] > > gcc/ > 2016-11-15 Richard Sandiford <richard.sandiford@arm.com> > Alan Hayward <alan.hayward@arm.com> > David Sherwood <david.sherwood@arm.com> > > * cprop.c (local_cprop_find_used_regs): Use df_read_modify_subreg_p. OK. jeff
diff --git a/gcc/cprop.c b/gcc/cprop.c index 6b4c0b8..31868a5 100644 --- a/gcc/cprop.c +++ b/gcc/cprop.c @@ -1161,9 +1161,7 @@ local_cprop_find_used_regs (rtx *xptr, void *data) return; case SUBREG: - /* Setting a subreg of a register larger than word_mode leaves - the non-written words unchanged. */ - if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD) + if (df_read_modify_subreg_p (x)) return; break;
local_cprop_find_used_regs punted on all multiword registers, with the comment: /* Setting a subreg of a register larger than word_mode leaves the non-written words unchanged. */ But this only applies if the outer mode is smaller than the inner mode. If they're the same size then writes to the subreg are a normal full update. This patch uses df_read_modify_subreg_p instead. A later patch adds more uses of the same routine, but this part had a (positive) effect on code generation for the testsuite whereas the others seemed to be simple clean-ups. Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install? Thanks, Richard [ This patch is part of the SVE series posted here: https://gcc.gnu.org/ml/gcc/2016-11/msg00030.html ] gcc/ 2016-11-15 Richard Sandiford <richard.sandiford@arm.com> Alan Hayward <alan.hayward@arm.com> David Sherwood <david.sherwood@arm.com> * cprop.c (local_cprop_find_used_regs): Use df_read_modify_subreg_p.