https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111904
Bug ID: 111904
Summary: Miscompilation with -O3
-fharden-control-flow-redundancy?
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
CC: aoliva at gcc dot gnu.org
Target Milestone: ---
Created attachment 56161
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56161&action=edit
memset_explicit-gone-wrong.tar.xz
Needs a trunk build from today or newer for -fharden-control-flow-redundancy.
1. git clone https://git.savannah.gnu.org/git/gnulib.git
2. ./gnulib-tool --single-configure --conditional-dependencies --create-testdir
--dir=uhoh memset_explicit
3. cd uhoh
4. ./configure CFLAGS="-O3 -fharden-control-flow-redundancy" # passes with -O2
5. make TESTS=test-memset_explicit check -j$(nproc)
```
$ ./test-memset_explicit
test_heap: address range is still mapped after free().
test_stack: count = 1000
test-memset_explicit.c:191: assertion 'count < 50' failed
Aborted (core dumped)
```
I'm not sure where it goes wrong yet. Attached
memset_explicit-gone-wrong.tar.xz has uhoh-O2 (good) and uhoh-O3 (bad) for
x86_64, but I reproduced this on arm64 too.
