qiurui
/
glibc
mirror of git://sourceware.org/git/glibc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

powerpc: Fix feraiseexcept and feclearexcept macros 

A recent change to fenvinline.h modified the check if __e is a
a power of 2 inside feraiseexcept and feclearexcept macros.  It
introduced the use of the powerof2 macro but also removed the
if statement checking whether __e != 0 before issuing an mtfsb*
instruction.  This is problematic because powerof2 (0) evaluates
to 1 and without the removed if __e is allowed to be 0 when
__builtin_clz is called.  In that case the value 32 is passed
to __MTFSB*, which is invalid.

This commit uses __builtin_popcount instead of powerof2 to fix this
issue and avoid the extra check for __e != 0.  This was the approach
used by the initial versions of that previous patch.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
This commit is contained in:
Matheus Castanho 2020-03-03 15:20:38 -03:00 committed by Tulio Magno Quites Machado Filho
parent af09e5e5d9
commit 1c252f0e7e
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sysdeps/powerpc/bits/fenvinline.h
View File

@ -75,7 +75,7 @@
int __e = __excepts; \
int __ret = 0; \
if (__builtin_constant_p (__e) \
&& powerof2 (__e) \
&& __builtin_popcount (__e) == 1 \
&& __e != FE_INVALID) \
{ \
__MTFSB1 ((__builtin_clz (__e))); \
@ -91,7 +91,7 @@
int __e = __excepts; \
int __ret = 0; \
if (__builtin_constant_p (__e) \
&& powerof2 (__e) \
&& __builtin_popcount (__e) == 1 \
&& __e != FE_INVALID) \
{ \
__MTFSB0 ((__builtin_clz (__e))); \