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* [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64
@ 2023-02-02 16:57 david.spickett at linaro dot org
2023-02-02 17:04 ` [Bug target/108642] ACLE function __arm_wsr missing " pinskia at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: david.spickett at linaro dot org @ 2023-02-02 16:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
Bug ID: 108642
Summary: ACLE function __arm_wsr missing when compiling in C++
mode for AArch64
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: david.spickett at linaro dot org
Target Milestone: ---
This was found by a user trying to compile llvm's libc (which is largely
written in c++) using g++ 8.5.0 for AArch64. I then tried versions up to 12.2.0
and a recent trunk build.
https://godbolt.org/z/qxaYxdTcv, and I've copied the details below.
The following source:
```
#include <stdint.h>
#include <arm_acle.h>
void writeStatusWord(uint32_t fpsr) { __arm_wsr("fpsr", fpsr); }
```
When compiled with g++ gives the error:
```
<source>:4:39: error: '__arm_wsr' was not declared in this scope
4 | void writeStatusWord(uint32_t fpsr) { __arm_wsr("fpsr", fpsr); }
| ^~~~~~~~~
```
When compiled as C, there is instead a warning and it does compile:
```
<source>:4:39: warning: implicit declaration of function '__arm_wsr'
[-Wimplicit-function-declaration]
4 | void writeStatusWord(uint32_t fpsr) { __arm_wsr("fpsr", fpsr); }
| ^~~~~~~~~
```
The expected result would be that in either mode, we can compile without errors
or warnings.
This __arm_wsr function should be present after including arm_acle.h according
to https://github.com/ARM-software/acle/releases/tag/r2022Q4 (acle-2022Q4.pdf
). See "11.1 Special register intrinsics".
I looked in the arm_acle.h gcc/g++ is including and see no reference to it.
Which makes me wonder if it's a compiler builtin that somehow isn't present for
C++.
Over in clang there is a builtin for it, that is then #defined into the
__arm_wsr name in the header.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/108642] ACLE function __arm_wsr missing for AArch64
2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
@ 2023-02-02 17:04 ` pinskia at gcc dot gnu.org
2023-02-02 17:06 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-02-02 17:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2023-02-02
Target| |aarch64-linux-gnu
Summary|ACLE function __arm_wsr |ACLE function __arm_wsr
|missing when compiling in |missing for AArch64
|C++ mode for AArch64 |
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
They are not implemented at all for either C or C++.
Confirmed.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/108642] ACLE function __arm_wsr missing for AArch64
2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
2023-02-02 17:04 ` [Bug target/108642] ACLE function __arm_wsr missing " pinskia at gcc dot gnu.org
@ 2023-02-02 17:06 ` pinskia at gcc dot gnu.org
2023-02-02 17:07 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-02-02 17:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the ACLE does not require "fpsr" to be supported either only
"o0:op1:CRn:CRm:op2" format is listed there ...
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/108642] ACLE function __arm_wsr missing for AArch64
2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
2023-02-02 17:04 ` [Bug target/108642] ACLE function __arm_wsr missing " pinskia at gcc dot gnu.org
2023-02-02 17:06 ` pinskia at gcc dot gnu.org
@ 2023-02-02 17:07 ` pinskia at gcc dot gnu.org
2023-02-02 17:09 ` david.spickett at linaro dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-02-02 17:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
GCC has a builtin already for getting fpsr already too:
__builtin_aarch64_get_fpsr
Which of course is not documented ...
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/108642] ACLE function __arm_wsr missing for AArch64
2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
` (2 preceding siblings ...)
2023-02-02 17:07 ` pinskia at gcc dot gnu.org
@ 2023-02-02 17:09 ` david.spickett at linaro dot org
2023-02-02 17:10 ` pinskia at gcc dot gnu.org
2023-02-03 16:25 ` david.spickett at linaro dot org
5 siblings, 0 replies; 7+ messages in thread
From: david.spickett at linaro dot org @ 2023-02-02 17:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
--- Comment #4 from David Spickett <david.spickett at linaro dot org> ---
Of course, I was just looking at at assembly output in compiler explorer and
then locally I didn't link the object. That's why it seemed to work.
Compiling and linking I get:
$ ./bin/aarch64-none-linux-gnu-gcc /tmp/test.c -o /tmp/test.o
/tmp/test.c: In function ‘writeStatusWord’:
/tmp/test.c:4:39: warning: implicit declaration of function ‘__arm_wsr’
[-Wimplicit-function-declaration]
4 | void writeStatusWord(uint32_t fpsr) { __arm_wsr("fpsr", fpsr); }
| ^~~~~~~~~
<...>aarch64-none-linux-gnu/bin/ld: /tmp/ccLie8Sh.o: in function
`writeStatusWord':
test.c:(.text+0x18): undefined reference to `__arm_wsr'
collect2: error: ld returned 1 exit status
Which makes more sense.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/108642] ACLE function __arm_wsr missing for AArch64
2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
` (3 preceding siblings ...)
2023-02-02 17:09 ` david.spickett at linaro dot org
@ 2023-02-02 17:10 ` pinskia at gcc dot gnu.org
2023-02-03 16:25 ` david.spickett at linaro dot org
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-02-02 17:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> Which of course is not documented ...
They are documented but not in a decent way:
https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc/AArch64-Built-in-Functions.html#AArch64-Built-in-Functions
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/108642] ACLE function __arm_wsr missing for AArch64
2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
` (4 preceding siblings ...)
2023-02-02 17:10 ` pinskia at gcc dot gnu.org
@ 2023-02-03 16:25 ` david.spickett at linaro dot org
5 siblings, 0 replies; 7+ messages in thread
From: david.spickett at linaro dot org @ 2023-02-03 16:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108642
--- Comment #6 from David Spickett <david.spickett at linaro dot org> ---
Thanks for the link, we'll try to use those when we detect g++.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-02-03 16:25 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2023-02-02 16:57 [Bug c++/108642] New: ACLE function __arm_wsr missing when compiling in C++ mode for AArch64 david.spickett at linaro dot org
2023-02-02 17:04 ` [Bug target/108642] ACLE function __arm_wsr missing " pinskia at gcc dot gnu.org
2023-02-02 17:06 ` pinskia at gcc dot gnu.org
2023-02-02 17:07 ` pinskia at gcc dot gnu.org
2023-02-02 17:09 ` david.spickett at linaro dot org
2023-02-02 17:10 ` pinskia at gcc dot gnu.org
2023-02-03 16:25 ` david.spickett at linaro dot org
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