https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107358
Bug ID: 107358
Summary: [13 Regression] i686-linux: Since
r13-3290-g98e341130f8798 code fails to build
libjxl-0/7.0 (vector float code)
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: slyfox at gcc dot gnu.org
CC: jakub at gcc dot gnu.org, jakub at redhat dot com
Target Milestone: ---
Initially observed build failure on libjxl-0.7.0 on i686-linux target.
Seems to happen only on i686-unknown-linux-gnu and only on -std=c++11.
PR107295 does not seem to be enough to fix it. Here is the minimal example:
// $ cat skcms.cc
// this works:
float approx_scal(float e) {
return e - 124.225514990f;
}
typedef float __attribute__((vector_size(4*sizeof(float)))) F;
// this fails:
// error: conversion of scalar 'long double' to vector 'F' {aka '__vector(4)
float'} involves truncation
F approx_vec(F e) {
return e - 124.225514990f;
//return e - 1.0f; // this works, does 'f' get ignored when float does not
fit?
}
$ g++-13 -fPIC -std=c++11 -o skcms.cc.o -c skcms.cc
skcms.cc: In function 'F approx_vec(F)':
skcms.cc:10:17: warning: SSE vector return without SSE enabled changes the ABI
[-Wpsabi]
10 | F approx_vec(F e) {
| ^
skcms.cc:11:14: error: conversion of scalar 'long double' to vector 'F' {aka
'__vector(4) float'} involves truncation
11 | return e - 124.225514990f;
| ~~^~~~~~~~~~~~~~~~
$ g++-12 -fPIC -std=c++11 -o skcms.cc.o -c skcms.cc
skcms.cc: In function 'F approx_vec(F)':
skcms.cc:10:17: warning: SSE vector return without SSE enabled changes the ABI
[-Wpsabi]
10 | F approx_vec(F e) {
| ^
skcms.cc:10:3: note: the ABI for passing parameters with 16-byte alignment has
changed in GCC 4.6
10 | F approx_vec(F e) {
| ^~~~~~~~~~
skcms.cc:10:3: warning: SSE vector argument without SSE enabled changes the ABI
Note: gcc-12 works, gcc-13 fails.
