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From: "rsandifo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/111267] [14 Regression] Codegen regression from i386 argument passing changes
Date: Mon, 22 Jan 2024 09:11:52 +0000	[thread overview]
Message-ID: <bug-111267-4-WZZD1K4gJb@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-111267-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111267

--- Comment #12 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
I don't object to the patch, but for the record: the current heuristics go back
a long way.  Although I reworked the pass to use rtl-ssa a few years ago, I
tried as far as possible to preserve the old heuristics (tested by making sure
that there were no unexplained differences over a large set of targets).

I wouldn't characterise the old heuristics as a logic error.  Although I didn't
write them, my understanding is that they were being deliberately conservative,
in particular due to the risk of introducing excess register pressure.

So this change seems potentially quite invasive for stage 4.  Perhaps it'll
work out — if so, great!  But if there is some fallout, I think we should lean
towards reverting the patch and revisiting in GCC 15.

  parent reply	other threads:[~2024-01-22  9:11 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-01 12:55 [Bug rtl-optimization/111267] New: " manolis.tsamis at vrull dot eu
2023-09-12 10:43 ` [Bug rtl-optimization/111267] [14 Regression] " rguenth at gcc dot gnu.org
2023-10-17 12:34 ` rguenth at gcc dot gnu.org
2023-10-20 22:42 ` roger at nextmovesoftware dot com
2023-10-20 22:49 ` roger at nextmovesoftware dot com
2024-01-05 10:43 ` jakub at gcc dot gnu.org
2024-01-12 15:49 ` jakub at gcc dot gnu.org
2024-01-12 19:06 ` roger at nextmovesoftware dot com
2024-01-14  0:09 ` roger at nextmovesoftware dot com
2024-01-14 12:10 ` roger at nextmovesoftware dot com
2024-01-15  7:32 ` rguenth at gcc dot gnu.org
2024-01-16  1:15 ` roger at nextmovesoftware dot com
2024-01-21 21:25 ` cvs-commit at gcc dot gnu.org
2024-01-22  9:11 ` rsandifo at gcc dot gnu.org [this message]
2024-01-25  7:51 ` mkuvyrkov at gcc dot gnu.org
2024-01-25  7:55 ` clyon at gcc dot gnu.org
2024-01-25  9:48 ` mkuvyrkov at gcc dot gnu.org
2024-02-16  9:12 ` roger at nextmovesoftware dot com

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