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[PATCH v3] powerpc: Refactor fenvinline.h
- From: Rogerio Alves <rcardoso at linux dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Cc: adhemerval dot zanella at linaro dot org, pc at us dot ibm dot com, Rogerio Alves <rcardoso at linux dot ibm dot com>
- Date: Mon, 10 Feb 2020 12:09:02 -0300
- Subject: [PATCH v3] powerpc: Refactor fenvinline.h
This patch refactor fenviline.h replaces some statements for
builtins.
---
* Changes in v3: Per Paul Clark review: replace __mtfsb[01] for
__MTFSB[01] to avoid name clashing with XL compiler (XL already
defined __mtfsb.
* Changes in v2: Per Adhemerval review: don not redefine _buitins use a
macro instead. Use of __builtin_popcount allows do eliminate the
if (e == 0) test. __builtin_popcount(e) == 1 for e = 0 validate false
while (e & (e - 1)) == 0 validate true if e = 0. Appended a comment
about the weird asm constrain i#*X. The warning only appear at GCC
versions 3 and below. If we even stops to support GCC 3 for installed
headers we may replace that for plain `i`.
sysdeps/powerpc/bits/fenvinline.h | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
diff --git a/sysdeps/powerpc/bits/fenvinline.h b/sysdeps/powerpc/bits/fenvinline.h
index 70689664e2..fec69b5a02 100644
--- a/sysdeps/powerpc/bits/fenvinline.h
+++ b/sysdeps/powerpc/bits/fenvinline.h
@@ -51,9 +51,19 @@
# define fegetround() __fegetround ()
# ifndef __NO_MATH_INLINES
+
+/* Builtins to mtfsb0 and mtfsb1 was introduced on GCC 9. */
+# if !__GNUC_PREREQ(9, 0)
/* The weird 'i#*X' constraints on the following suppress a gcc
warning when __excepts is not a constant. Otherwise, they mean the
- same as just plain 'i'. */
+ same as just plain 'i'. This warning only happens in old GCC
+ versions (gcc 3 or less). Otherwise plain 'i' works fine. */
+# define __MTFSB0(__b) __asm__ __volatile__ ("mtfsb0 %0" : : "i#*X" (__b))
+# define __MTFSB1(__b) __asm__ __volatile__ ("mtfsb1 %0" : : "i#*X" (__b))
+# else
+# define __MTFSB0(__b) __builtin_mtfsb0 (__b)
+# define __MTFSB1(__b) __builtin_mtfsb1 (__b)
+# endif
# if __GNUC_PREREQ(3, 4)
@@ -61,15 +71,12 @@
# define feraiseexcept(__excepts) \
(__extension__ ({ \
int __e = __excepts; \
- int __ret; \
+ int __ret = 0; \
if (__builtin_constant_p (__e) \
- && (__e & (__e - 1)) == 0 \
+ && (__builtin_popcount (__e) == 1) \
&& __e != FE_INVALID) \
{ \
- if (__e != 0) \
- __asm__ __volatile__ ("mtfsb1 %0" \
- : : "i#*X" (__builtin_clz (__e))); \
- __ret = 0; \
+ __MTFSB1 ((__builtin_clz (__e))); \
} \
else \
__ret = feraiseexcept (__e); \
@@ -80,15 +87,12 @@
# define feclearexcept(__excepts) \
(__extension__ ({ \
int __e = __excepts; \
- int __ret; \
+ int __ret = 0; \
if (__builtin_constant_p (__e) \
- && (__e & (__e - 1)) == 0 \
+ && (__builtin_popcount (__e) == 1) \
&& __e != FE_INVALID) \
{ \
- if (__e != 0) \
- __asm__ __volatile__ ("mtfsb0 %0" \
- : : "i#*X" (__builtin_clz (__e))); \
- __ret = 0; \
+ __MTFSB0 ((__builtin_clz (__e))); \
} \
else \
__ret = feclearexcept (__e); \
--
2.17.1