From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id B07493806BF1; Wed,  5 Jun 2024 05:37:34 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B07493806BF1
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1717565854;
	bh=9KJ5v/IEhJ0vAQYKPe3VyGerKXu6G1hV+KTJvjn54EM=;
	h=From:To:Subject:Date:From;
	b=o2cVRdZ68uMhseyN7QKbG+9DuUDTih0sENr9DRfU4zOxZAvjHg0Y3MZffYZ2FHlwF
	 5JcRE7IjkE82QaY0Rjw6d0l+AsS9EbhaHqCNJwseryl+KT41lnNdXMY4DRUXJeyAPR
	 VZ6K5E4Gk0r9OzDzcPYZydPYbZYyCUwKGuc3jfuY=
From: "gus at projectgus dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/115354] New: Large -Os code size increase
 related to -ftree-sra
Date: Wed, 05 Jun 2024 05:37:33 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 14.1.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: gus at projectgus dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
 attachments.created
Message-ID: <bug-115354-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D115354

            Bug ID: 115354
           Summary: Large -Os code size increase related to -ftree-sra
           Product: gcc
           Version: 14.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gus at projectgus dot com
  Target Milestone: ---

Created attachment 58353
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D58353&action=3Dedit
Source file shows code size increase in mp_parse function

After upgrading arm-none-eabi-gcc from 13.2 to 14.1 we noticed some increas=
es
in code size when compiling the MicroPython project with -Os.

Bisecting turned up a commit that introduces a 15% code size increase in an
(admittedly quite complex) function.

The commit is aae723d3 "sra: SRA of non-escaped aggregates passed by refere=
nce
to calls".

GCC 13.2 and the parent of commit aae723d3 both produce a 2846 byte text
section when building the attached code.

GCC 14.1, commit aae723d3, and recent master branch all produce a 3282 byte
text section.

Full compiler command line is "arm-none-eabi-gcc -Wall -Wextra -std=3Dc99
-mcpu=3Dcortex-m4 -Os -c"

If -fno-tree-sra argument is added then the text section reverts to 2846 by=
tes.
Assembler output from commit aae723d3 passing -fno-tree-sra is identical to
output from the parent commit without -fno-tree-sra.

Unfortunately the function is quite complex and includes gotos and calls to
noreturn functions. I haven't been able to isolate a smaller test case but I
thought it was worth reporting anyway, as the size jump is quite noticeable.

Version and configuration details for the local test builds:

> Target: arm-none-eabi
> Configured with: /home/gus/dev/gcc/configure --target=3Darm-none-eabi --p=
refix=3D/home/gus/ry/george/tmp/gcc-temp-aae723d3 --with-sysroot=3D/home/gu=
s/ry/george/tmp/gcc-temp-aae723d3/arm-none-eabi --enable-languages=3Dc --en=
able-plugins --disable-decimal-float --disable-libffi --disable-libgomp --d=
isable-libmudflap --disable-libquadmath --disable-libssp --disable-libstdcx=
x-pch --disable-nls --disable-shared --disable-threads --disable-tls --with=
-gnu-as --with-gnu-ld --with-system-zlib --with-newlib --with-headers=3D/ho=
me/gus/ry/george/tmp/gcc-temp-aae723d3/arm-none-eabi/include --with-python-=
dir=3Dshare/gcc-arm-none-eabi --with-gmp --with-mpfr --with-mpc --with-isl =
--with-libelf --enable-gnu-indirect-function --with-host-libstdcxx=3D'-stat=
ic-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm' --with-multilib-list=3Drmpro=
file
> gcc version 14.0.0 20231124 (experimental) (GCC)=