https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120420
Bug ID: 120420
Summary: Improving __gnat_decode() gcc/ada/adadecode.c
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
Assignee: unassigned at gcc dot gnu.org
Reporter: kaelfandrew at gmail dot com
CC: dkm at gcc dot gnu.org
Target Milestone: ---
Created attachment 61507
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=61507&action=edit
Patch
With commit 66e9a4f3083356b064cc64651edad466a56f762b at gcc/ada/adadecode.c,
__gnat_decode() uses many strlen() for has_suffix().
https://godbolt.org/z/71chMqq4K with:
=====================
Using built-in specs.
COLLECT_GCC=/opt/compiler-explorer/gcc-snapshot/bin/gcc
Target: x86_64-linux-gnu
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Compiler executable checksum: 62a470ccee599c6960b9a1b705563b2d
COMPILER_PATH=/opt/compiler-explorer/gcc-trunk-20250523/bin/../libexec/gcc/x86_64-linux-gnu/16.0.0/:/opt/compiler-explorer/gcc-trunk-20250523/bin/../libexec/gcc/x86_64-linux-gnu/:/opt/compiler-explorer/gcc-trunk-20250523/bin/../libexec/gcc/:/opt/compiler-explorer/gcc-trunk-20250523/bin/../lib/gcc/x86_64-linux-gnu/16.0.0/../../../../x86_64-linux-gnu/bin/
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'-masm=intel' '-fno-verbose-asm' '-S' '-v' '-mtune=generic' '-march=x86-64'
'-dumpdir' '/app/output.'
Compiler returned: 0
====================
Shows the generated assembly uses many strlen() in f0_slow() with flags -O3
-fallow-store-data-races.
The patch attachment should make it faster.
