https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88100
Bug ID: 88100
Summary: no warning reported when value for
vec_splat_{su}{8,16} would overflow
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: pc at gcc dot gnu.org
Target Milestone: ---
Created attachment 45036
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45036&action=edit
test case
$ cat bug.c
#include <altivec.h>
void foo() {
signed char cs0 = 0x100;
unsigned char cu0= 0x100;
signed short ss0 = 0x10000;
unsigned short su0= 0x10000;
signed int is0 = 0x100000000;
unsigned int iu0= 0x100000000;
vector signed char v8 = vec_splat_s8(256);
vector unsigned char v11 = vec_splat_u8(256);
vector signed short v12 = vec_splat_s16(0x10000);
vector unsigned short v13 = vec_splat_u16(0x10000);
vector signed int v14 = vec_splat_s32(0x100000000);
vector unsigned int v15 = vec_splat_u32(0x100000000);
}
$ gcc -c bug.c
bug.c: In function ‘foo’:
bug.c:3:21: warning: overflow in conversion from ‘int’ to ‘signed char’ changes
value from ‘256’ to ‘0’ [-Woverflow]
signed char cs0 = 0x100;
^~~~~
bug.c:4:22: warning: unsigned conversion from ‘int’ to ‘unsigned char’ changes
value from ‘256’ to ‘0’ [-Woverflow]
unsigned char cu0= 0x100;
^~~~~
bug.c:5:22: warning: overflow in conversion from ‘int’ to ‘short int’ changes
value from ‘65536’ to ‘0’ [-Woverflow]
signed short ss0 = 0x10000;
^~~~~~~
bug.c:6:23: warning: unsigned conversion from ‘int’ to ‘short unsigned int’
changes value from ‘65536’ to ‘0’ [-Woverflow]
unsigned short su0= 0x10000;
^~~~~~~
bug.c:7:20: warning: overflow in conversion from ‘long int’ to ‘int’ changes
value from ‘4294967296’ to ‘0’ [-Woverflow]
signed int is0 = 0x100000000;
^~~~~~~~~~~
bug.c:8:21: warning: unsigned conversion from ‘long int’ to ‘unsigned int’
changes value from ‘4294967296’ to ‘0’ [-Woverflow]
unsigned int iu0= 0x100000000;
^~~~~~~~~~~
bug.c:13:27: warning: overflow in conversion from ‘long int’ to ‘int’ changes
value from ‘4294967296’ to ‘0’ [-Woverflow]
vector signed int v14 = vec_splat_s32(0x100000000);
^~~~~~~~~~~~~
bug.c:14:29: warning: overflow in conversion from ‘long int’ to ‘int’ changes
value from ‘4294967296’ to ‘0’ [-Woverflow]
vector unsigned int v15 = vec_splat_u32(0x100000000);
^~~~~~~~~~~~~
--
Note: no warnings for the vector char and vector short types.
