https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110736
Bug ID: 110736
Summary: gcc: internal compiler error: in change_stack, at
reg-stack.cc:2709
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: 141242068 at smail dot nju.edu.cn
Target Milestone: ---
The bug triggering program:
```
long double a, b;
long double f(long double x) {
asm("sqxbr\t%0,%1" : "=f"(a) : "f"(x));
return a;
}
int main(void) {
return b / f(0x1.0000000000001p+0L);
}
```
When attempting to compile it using the option `gcc-14 -Os small.c`, gcc
crashes:
```
<source>: In function 'f':
<source>:3:3: error: output constraint 0 must specify a single register
3 | asm("sqxbr\t%0,%1" : "=f"(a) : "f"(x));
| ^~~
during RTL pass: stack
<source>:5:1: internal compiler error: in change_stack, at reg-stack.cc:2709
5 | }
| ^
0x21594ee internal_error(char const*, ...)
???:0
0x9cf35e fancy_abort(char const*, int, char const*)
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
```
This crash can be verified at compiler explorer:
https://gcc.godbolt.org/z/EKrY7s576
