https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114567
Bug ID: 114567
Summary: rs6000: explicit _Float128 doesn't generate optimal
code
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: linkw at gcc dot gnu.org
Target Milestone: ---
This is an issue which I happened to spot when I have been working on patches
for PR112993.
=== test case ===
#define TYPE _Float128
#ifdef LD
#undef TYPE
#define TYPE long double
#endif
int sbm (TYPE *a) { return __builtin_signbit (*a); }
==================
/opt/gcc-nightly/trunk/bin/gcc -mcpu=power8 -mvsx -O2 -mabi=ieeelongdouble
-Wno-psabi test.c -DLD -S -o ref.s
/opt/gcc-nightly/trunk/bin/gcc -mcpu=power8 -mvsx -O2 -mabi=ibmlongdouble
-Wno-psabi test.c -S -o float128.s
diff -Nur ref.s float128.s
--- ref.s 2024-03-18 05:41:00.302208975 -0400
+++ float128.s 2024-03-18 05:41:00.392205513 -0400
@@ -9,7 +9,10 @@
sbm:
.LFB0:
.cfi_startproc
- ld 3,8(3)
+ rldicr 3,3,0,59
+ lxvd2x 0,0,3
+ xxpermdi 0,0,0,2
+ mfvsrd 3,0
srdi 3,3,63
blr
.long 0
