https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63673
Bug ID: 63673
Summary: VSX intrinsic vec_vsx_ld fails to compile with double,
maps to wrong instructions with float
Product: gcc
Version: 4.9.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: markos at freevec dot org
Created attachment 33836
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33836&action=edit
failing to compile testcase for vec_vsx_ld using doubles
These are actually two issues, but I'm filing a single bug report as it looks
like they are related.
First the build error, I've created a small failing testcase (also attached):
--
#include <altivec.h>
int main() {
double __attribute__((aligned(16))) d[4] = {0.0, 1.0, 2.0, 3.0 };
vector double v = vec_vsx_ld(8, d); // should load {1.0, 2.0}
}
--
This fails to compile under Debian gcc (4.9.1-19), with the following error:
$ gcc vec_vsx_ld_fail.c -c
vec_vsx_ld_fail.c: In function ‘main’:
vec_vsx_ld_fail.c:6:2: error: invalid parameter combination for AltiVec
intrinsic
vector double v = vec_vsx_ld(4, d); // should load {1.0, 2.0}
Casting d to (float *) makes it compile, but vec_vsx_ld intrinsic definitely
should handle double parameters, so I think this is a bug.
Now the second problem, a similar testcase for float (also attached):
--
#include <altivec.h>
int main() {
float __attribute__((aligned(16))) f[8] = {0.0, 1.0, 2.0, 3.0, 4.0,
5.0, 6.0, 7.0 };
vector float v = vec_vsx_ld(4, f); // should load {1.0, 2.0, 3.0, 4.0}
}
--
This does compile, but the asm output uses the lxvd2x asm instruction, when
according the the ISA, lxvw4x should be used -at least according to my
understanding (page 359, Power ISA 2.07). Asm output also attached.
