powerpc: Use faster means to access FPSCR when possible in some cases

[external/glibc.git] / sysdeps / powerpc / bits / fenvinline.h

diff --git a/sysdeps/powerpc/bits/fenvinline.h b/sysdeps/powerpc/bits/fenvinline.h
index 7079d1a..56ac0f3 100644 (file)
--- a/sysdeps/powerpc/bits/fenvinline.h
+++ b/sysdeps/powerpc/bits/fenvinline.h
@@ -18,13 +18,36 @@
 
 #if defined __GNUC__ && !defined _SOFT_FLOAT && !defined __NO_FPRS__
 
-/* Inline definition for fegetround.  */
-# define __fegetround() \
-  (__extension__  ({ int __fegetround_result;                                \
-                    __asm__ __volatile__                                     \
-                      ("mcrfs 7,7 ; mfcr %0"                                 \
-                       : "=r"(__fegetround_result) : : "cr7");               \
-                    __fegetround_result & 3; }))
+/* Inline definitions for fegetround.  */
+# define __fegetround_ISA300()                                         \
+  (__extension__  ({                                                   \
+    union { double __d; unsigned long long __ll; } __u;                        \
+    __asm__ __volatile__ (                                             \
+      ".machine push; .machine \"power9\"; mffsl %0; .machine pop"     \
+      : "=f" (__u.__d));                                               \
+    __u.__ll & 0x0000000000000003LL;                                   \
+  }))
+
+# define __fegetround_ISA2()                                           \
+  (__extension__  ({                                                   \
+     int __fegetround_result;                                          \
+     __asm__ __volatile__ ("mcrfs 7,7 ; mfcr %0"                       \
+                          : "=r"(__fegetround_result) : : "cr7");      \
+     __fegetround_result & 3;                                          \
+  }))
+
+# ifdef _ARCH_PWR9
+#  define __fegetround() __fegetround_ISA300()
+# elif defined __BUILTIN_CPU_SUPPORTS__
+#  define __fegetround()                                               \
+  (__glibc_likely (__builtin_cpu_supports ("arch_3_00"))               \
+   ? __fegetround_ISA300()                                             \
+   : __fegetround_ISA2()                                               \
+  )
+# else
+#  define __fegetround() __fegetround_ISA2()
+# endif
+
 # define fegetround() __fegetround ()
 
 # ifndef __NO_MATH_INLINES