public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc r12-7620] Fix DImode to TImode sign extend issue
@ 2022-03-12 0:47 Michael Meissner
0 siblings, 0 replies; only message in thread
From: Michael Meissner @ 2022-03-12 0:47 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:3cb27b85a7b977958d53e1a29596ba211d21dde2
commit r12-7620-g3cb27b85a7b977958d53e1a29596ba211d21dde2
Author: Michael Meissner <meissner@linux.ibm.com>
Date: Fri Mar 11 19:47:09 2022 -0500
Fix DImode to TImode sign extend issue
PR target/104868 had had an issue where my code that updated the DImode to
TImode sign extension for power10 failed. In looking at the failure
message, the reason is when extendditi2 tries to split the insn, it
generates an insn that does not satisfy its constraints:
(set (reg:V2DI 65 1)
(vec_duplicate:V2DI (reg:DI 0)))
The reason is vsx_splat_v2di does not allow GPR register 0 when the will
be generating a mtvsrdd instruction. In the definition of the mtvsrdd
instruction, if the RA register is 0, it means clear the upper 64 bits of
the vector instead of moving register GPR 0 to those bits.
When I wrote the extendditi2 pattern, I forgot that mtvsrdd had that
behavior so I used a 'r' constraint instead of 'b'. In the rare case
where the value is in GPR register 0, this split will fail.
This patch uses the right constraint for extendditi2.
2022-03-11 Michael Meissner <meissner@linux.ibm.com>
gcc/
PR target/104868
* config/rs6000/vsx.md (extendditi2): Use a 'b' constraint when
moving from a GPR register to an Altivec register.
Diff:
---
gcc/config/rs6000/vsx.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index d0fb92f5985..15bd86dfdfb 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -5033,7 +5033,7 @@
;; generate the vextsd2q instruction.
(define_insn_and_split "extendditi2"
[(set (match_operand:TI 0 "register_operand" "=r,r,v,v,v")
- (sign_extend:TI (match_operand:DI 1 "input_operand" "r,m,r,wa,Z")))
+ (sign_extend:TI (match_operand:DI 1 "input_operand" "r,m,b,wa,Z")))
(clobber (reg:DI CA_REGNO))]
"TARGET_POWERPC64 && TARGET_POWER10"
"#"
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2022-03-12 0:47 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-12 0:47 [gcc r12-7620] Fix DImode to TImode sign extend issue Michael Meissner
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).