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* [Bug c/113795] New: armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error
@ 2024-02-07 6:09 keithp at keithp dot com
2024-02-07 6:11 ` [Bug c/113795] " keithp at keithp dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: keithp at keithp dot com @ 2024-02-07 6:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113795
Bug ID: 113795
Summary: armv8.1m-m.main+pacbti -mbranch-protection=standard
-O2 compile error
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: keithp at keithp dot com
Target Milestone: ---
Created attachment 57348
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57348&action=edit
Reasonably short test case.
A tail-call indirect branch is miscompiled in the attached example.
Without -mbranch-protection=standard:
```
.L2:
ldr r4, .L25+4
movs r0, #0
ldr r4, [r4, #24]
mov ip, r4
str r4, [sp, #4]
add sp, sp, #28
@ sp needed
pop {r4, r5, r6, r7, r8, r9, r10, fp, lr}
bx ip
```
With -mbranch-protection=standard:
```
.L2:
movs r0, #0
ldr r4, .L25+4
ldr r4, [r4, #24]
str r4, [sp, #4]
add sp, sp, #24
@ sp needed
pop {r4, r5, r6, r7, r8, r9, r10, fp, ip, lr}
aut ip, lr, sp
bx ip
```
Note that in the latter example, the `ip` register doesn't get copied from
`r4`, presumably because `ip` gets clobbered by the PAC operation. That leaves
the indirect branch at the end jumping to a random address.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/113795] armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error
2024-02-07 6:09 [Bug c/113795] New: armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error keithp at keithp dot com
@ 2024-02-07 6:11 ` keithp at keithp dot com
2024-02-07 6:20 ` keithp at keithp dot com
2024-02-08 11:17 ` [Bug target/113795] " rearnsha at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: keithp at keithp dot com @ 2024-02-07 6:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113795
--- Comment #1 from keithp at keithp dot com <keithp at keithp dot com> ---
compiler command:
arm-none-eabi-gcc \
-std=c18 \
-O2 \
-mthumb \
-march=armv8.1-m.main+pacbti+fp \
-mbranch-protection=standard \
-o \
bar.s \
-S \
bar.c
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/113795] armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error
2024-02-07 6:09 [Bug c/113795] New: armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error keithp at keithp dot com
2024-02-07 6:11 ` [Bug c/113795] " keithp at keithp dot com
@ 2024-02-07 6:20 ` keithp at keithp dot com
2024-02-08 11:17 ` [Bug target/113795] " rearnsha at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: keithp at keithp dot com @ 2024-02-07 6:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113795
keithp at keithp dot com <keithp at keithp dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Version|13.2.1 |14.0
--- Comment #2 from keithp at keithp dot com <keithp at keithp dot com> ---
Just reproduced this with version 14.0.1 (debian unstable
arm-linux-gnueabi-gcc-14 package)
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/113795] armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error
2024-02-07 6:09 [Bug c/113795] New: armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error keithp at keithp dot com
2024-02-07 6:11 ` [Bug c/113795] " keithp at keithp dot com
2024-02-07 6:20 ` keithp at keithp dot com
@ 2024-02-08 11:17 ` rearnsha at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rearnsha at gcc dot gnu.org @ 2024-02-08 11:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113795
Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |DUPLICATE
Status|UNCONFIRMED |RESOLVED
--- Comment #3 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Same as 113780
*** This bug has been marked as a duplicate of bug 113780 ***
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-02-08 11:17 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2024-02-07 6:09 [Bug c/113795] New: armv8.1m-m.main+pacbti -mbranch-protection=standard -O2 compile error keithp at keithp dot com
2024-02-07 6:11 ` [Bug c/113795] " keithp at keithp dot com
2024-02-07 6:20 ` keithp at keithp dot com
2024-02-08 11:17 ` [Bug target/113795] " rearnsha at gcc dot gnu.org
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