https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109939
Bug ID: 109939
Summary: Invalid return type for __builtin_arm_ssat: Unsigned
instead of signed
Product: gcc
Version: 13.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: dev at benjarobin dot fr
Target Milestone: ---
The warning is triggered with the following test case:
```
int dbg_ssat_out;
int dbg_ssat_in;
void test_arm_ssat(void)
{
dbg_ssat_out = __builtin_arm_ssat(dbg_ssat_in, 16);
}
```
Compile it using this command line:
arm-none-eabi-gcc -mcpu=cortex-m4 -Wall -Wconversion -c t.c -o t.o
The following output is generated:
```
t.c: In function 'test_arm_ssat':
t.c:7:20: warning: conversion to 'int' from 'unsigned int' may change the sign
of the result [-Wsign-conversion]
7 | dbg_ssat_out = __builtin_arm_ssat(dbg_ssat_in, 16);
| ^~~~~~~~~~~~~~~~~~
```
This is an issue since SSAT assembly instruction returns a signed value and not
an unsigned integer.
Maybe this line is wrong (I am not an expert about GCC):
https://github.com/gcc-mirror/gcc/blob/releases/gcc-13.1.0/gcc/config/arm/arm-builtins.cc#L100
