From: Jiufu Guo <guojiufu@linux.ibm.com>
To: gcc-patches@gcc.gnu.org
Cc: segher@kernel.crashing.org, dje.gcc@gmail.com, linkw@gcc.gnu.org,
guojiufu@linux.ibm.com, meissner@linux.ibm.com
Subject: [PATCH 2/2] allow constant splitter run in split1 pass
Date: Thu, 1 Sep 2022 11:24:07 +0800 [thread overview]
Message-ID: <20220901032407.23751-1-guojiufu@linux.ibm.com> (raw)
Hi,
Currently, these two splitters (touched in this patch) are using predicate
`int_reg_operand_not_pseudo`, then they work in split2 pass after RA in
most times, and can not run before RA.
It would not be a bad idea to allow these splitters before RA. Then more
passes (between split1 and split2) could optimize the emitted instructions.
And if splitting before RA, for these constant splitters, we may have more
freedom to create pseduo to generate more parallel instructions.
For the example in the leading patch [PATCH 1/2]: pli+plit+rldimi would be
better than pli+sldi+paddi.
Test this patch with spec, we could see performance gain some times; while
the improvement is not stable and woud caused by the patch indirectly.
This patch pass boostrap and regtest on ppc64le(includes p10).
Is it ok for trunk? Thanks for comments!
BR,
Jeff(Jiufu)
gcc/ChangeLog:
* config/rs6000/rs6000.md (const splitter): Update predicate.
---
gcc/config/rs6000/rs6000.md | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 1367a2cb779..ec39676f628 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -9641,7 +9641,7 @@ (define_insn "*movdi_internal64"
; Some DImode loads are best done as a load of -1 followed by a mask
; instruction.
(define_split
- [(set (match_operand:DI 0 "int_reg_operand_not_pseudo")
+ [(set (match_operand:DI 0 "int_reg_operand")
(match_operand:DI 1 "const_int_operand"))]
"TARGET_POWERPC64
&& num_insns_constant (operands[1], DImode) > 1
@@ -9659,7 +9659,7 @@ (define_split
;; When non-easy constants can go in the TOC, this should use
;; easy_fp_constant predicate.
(define_split
- [(set (match_operand:DI 0 "int_reg_operand_not_pseudo")
+ [(set (match_operand:DI 0 "int_reg_operand")
(match_operand:DI 1 "const_int_operand"))]
"TARGET_POWERPC64 && num_insns_constant (operands[1], DImode) > 1"
[(set (match_dup 0) (match_dup 2))
--
2.17.1
next reply other threads:[~2022-09-01 3:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 3:24 Jiufu Guo [this message]
2022-09-01 22:33 ` Segher Boessenkool
2022-09-02 3:35 ` Jiufu Guo
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