https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118097
Bug ID: 118097
Summary: recent bug with -O2, but not -O1
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: dcb314 at hotmail dot com
Target Milestone: ---
Created attachment 59901
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59901&action=edit
C source code
For the attached C code, from csmith:
foundBugs $ /home/dcb40b/gcc/results.20241215.asan.ubsan/bin/gcc -w -O2
-Werror=uninitialized -Werror=aggressive-loop-optimizations
-Werror=sequence-point bug1071.c && ./a.out 1 | grep "g_90 :"
...checksum after hashing g_90 : F239C101
foundBugs $ /home/dcb40b/gcc/results.20241217.asan.ubsan/bin/gcc -w -O2
-Werror=uninitialized -Werror=aggressive-loop-optimizations
-Werror=sequence-point bug1071.c && ./a.out 1 | grep "g_90 :"
...checksum after hashing g_90 : B01CC67C
foundBugs $ /home/dcb40b/gcc/results.20241215.asan.ubsan/bin/gcc -w -O1
-Werror=uninitialized -Werror=aggressive-loop-optimizations
-Werror=sequence-point bug1071.c && ./a.out 1 | grep "g_90 :"
...checksum after hashing g_90 : F239C101
foundBugs $ /home/dcb40b/gcc/results.20241217.asan.ubsan/bin/gcc -w -O1
-Werror=uninitialized -Werror=aggressive-loop-optimizations
-Werror=sequence-point bug1071.c && ./a.out 1 | grep "g_90 :"
...checksum after hashing g_90 : F239C101
So the 20241217 compiler with -O2 looks suspicious.
foundBugs $ /home/dcb40b/gcc/results.20241215.asan.ubsan/bin/gcc -v 2>&1 | grep
exp
gcc version 15.0.0 20241215 (experimental) (fe545ea3d82bc2ba)
foundBugs $ /home/dcb40b/gcc/results.20241217.asan.ubsan/bin/gcc -v 2>&1 | grep
exp
gcc version 15.0.0 20241217 (experimental) (40e5636e086e51f5)
foundBugs $
I have a reduction running.
