Re: [PATCH] Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode.
On Thu, May 25, 2023 at 10:29:47AM -0400, Vladimir Makarov wrote:
>
> On 5/17/23 02:57, liuhongt wrote:
> >r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost
> >calculation when the preferred register class are not known yet.
> >It regressed powerpc PR109610 and PR109858, it looks too aggressive to use
> >NO_REGS when mode can be allocated with GENERAL_REGS.
> >The patch takes a step back, still use GENERAL_REGS when
> >hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS.
> >Kewen confirmed the patch fixed PR109858, I vefiried it also fixed
> >PR109610.
> >
> >Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> >No big performance impact for SPEC2017 on icelake server.
> >Ok for trunk?
> >
> >gcc/ChangeLog:
> >
> > * ira-costs.cc (scan_one_insn): Only use NO_REGS in cost
> > calculation when !hard_regno_mode_ok for GENERAL_REGS and
> > mode, otherwise still use GENERAL_REGS.
>
> Thank you for the patch. It looks good for me. It is ok to commit it
> into the trunk.
Thanks everyone involved for fixing this nasty regression! Much
appreciated.
Segher
Re: [PATCH] Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode.
On 5/17/23 02:57, liuhongt wrote:
r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost
calculation when the preferred register class are not known yet.
It regressed powerpc PR109610 and PR109858, it looks too aggressive to use
NO_REGS when mode can be allocated with GENERAL_REGS.
The patch takes a step back, still use GENERAL_REGS when
hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS.
Kewen confirmed the patch fixed PR109858, I vefiried it also fixed PR109610.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
No big performance impact for SPEC2017 on icelake server.
Ok for trunk?
gcc/ChangeLog:
* ira-costs.cc (scan_one_insn): Only use NO_REGS in cost
calculation when !hard_regno_mode_ok for GENERAL_REGS and
mode, otherwise still use GENERAL_REGS.
Thank you for the patch. It looks good for me. It is ok to commit it
into the trunk.
Re: [PATCH] Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode.
On 5/17/23 00:57, liuhongt via Gcc-patches wrote:
r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost
calculation when the preferred register class are not known yet.
It regressed powerpc PR109610 and PR109858, it looks too aggressive to use
NO_REGS when mode can be allocated with GENERAL_REGS.
The patch takes a step back, still use GENERAL_REGS when
hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS.
Kewen confirmed the patch fixed PR109858, I vefiried it also fixed PR109610.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
No big performance impact for SPEC2017 on icelake server.
Ok for trunk?
gcc/ChangeLog:
* ira-costs.cc (scan_one_insn): Only use NO_REGS in cost
calculation when !hard_regno_mode_ok for GENERAL_REGS and
mode, otherwise still use GENERAL_REGS.
BTW, Vlad is on PTO right now. I'm sure he'll handle this after he
returns and starts digging out of all the stuff that's piled up.
jeff
[PATCH] Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode.
r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost
calculation when the preferred register class are not known yet.
It regressed powerpc PR109610 and PR109858, it looks too aggressive to use
NO_REGS when mode can be allocated with GENERAL_REGS.
The patch takes a step back, still use GENERAL_REGS when
hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS.
Kewen confirmed the patch fixed PR109858, I vefiried it also fixed PR109610.
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
No big performance impact for SPEC2017 on icelake server.
Ok for trunk?
gcc/ChangeLog:
* ira-costs.cc (scan_one_insn): Only use NO_REGS in cost
calculation when !hard_regno_mode_ok for GENERAL_REGS and
mode, otherwise still use GENERAL_REGS.
---
gcc/ira-costs.cc | 12
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/gcc/ira-costs.cc b/gcc/ira-costs.cc
index d2a801ab9b0..ae8304ff938 100644
--- a/gcc/ira-costs.cc
+++ b/gcc/ira-costs.cc
@@ -1572,12 +1572,16 @@ scan_one_insn (rtx_insn *insn)
&& (! ira_use_lra_p || ! pic_offset_table_rtx
|| ! contains_symbol_ref_p (XEXP (note, 0
{
- /* Costs for NO_REGS are used in cost calculation on the
-1st pass when the preferred register classes are not
-known yet. In this case we take the best scenario. */
- enum reg_class cl = NO_REGS;
+ enum reg_class cl = GENERAL_REGS;
rtx reg = SET_DEST (set);
int num = COST_INDEX (REGNO (reg));
+ /* Costs for NO_REGS are used in cost calculation on the
+1st pass when the preferred register classes are not
+known yet. In this case we take the best scenario when
+mode can't be put into GENERAL_REGS. */
+ if (!targetm.hard_regno_mode_ok (ira_class_hard_regs[cl][0],
+ GET_MODE (reg)))
+ cl = NO_REGS;
COSTS (costs, num)->mem_cost
-= ira_memory_move_cost[GET_MODE (reg)][cl][1] * frequency;
--
2.39.1.388.g2fc9e9ca3c
