glibc/glibc-rh1956357-1.patch

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commit 56c81132ccc6f468fa4fc29c536db060e18e9d87
Author: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
Date: Tue Feb 23 14:14:37 2021 -0300
powerpc: Add optimized ilogb* for POWER9
The instructions xsxexpdp and xsxexpqp introduced on POWER9 extract
the exponent from a double-precision and quad-precision floating-point
respectively, thus they can be used to improve ilogb, ilogbf and ilogbf128.
diff --git a/sysdeps/powerpc/fpu/math_private.h b/sysdeps/powerpc/fpu/math_private.h
index e642d6c8237578ea..5bbc468829062a48 100644
--- a/sysdeps/powerpc/fpu/math_private.h
+++ b/sysdeps/powerpc/fpu/math_private.h
@@ -26,7 +26,28 @@
#include_next <math_private.h>
-#if defined _ARCH_PWR9 && __HAVE_DISTINCT_FLOAT128
+#ifdef _ARCH_PWR9
+
+#if __GNUC_PREREQ (8, 0)
+# define _GL_HAS_BUILTIN_ILOGB 1
+#elif defined __has_builtin
+# define _GL_HAS_BUILTIN_ILOGB __has_builtin (__builtin_vsx_scalar_extract_exp)
+#else
+# define _GL_HAS_BUILTIN_ILOGB 0
+#endif
+
+#define __builtin_test_dc_ilogbf __builtin_test_dc_ilogb
+#define __builtin_ilogbf __builtin_ilogb
+
+#define __builtin_test_dc_ilogb(x, y) \
+ __builtin_vsx_scalar_test_data_class_dp(x, y)
+#define __builtin_ilogb(x) __builtin_vsx_scalar_extract_exp(x) - 0x3ff
+
+#define __builtin_test_dc_ilogbf128(x, y) \
+ __builtin_vsx_scalar_test_data_class_qp(x, y)
+#define __builtin_ilogbf128(x) __builtin_vsx_scalar_extract_expq(x) - 0x3fff
+
+#if __HAVE_DISTINCT_FLOAT128
extern __always_inline _Float128
__ieee754_sqrtf128 (_Float128 __x)
{
@@ -35,6 +56,9 @@ __ieee754_sqrtf128 (_Float128 __x)
return __z;
}
#endif
+#else /* !_ARCH_PWR9 */
+#define _GL_HAS_BUILTIN_ILOGB 0
+#endif
#if defined _ARCH_PWR5X
diff --git a/sysdeps/powerpc/powerpc64/le/fpu/w_ilogb_template.c b/sysdeps/powerpc/powerpc64/le/fpu/w_ilogb_template.c
new file mode 100644
index 0000000000000000..b5c1c0aa9db86f3d
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/le/fpu/w_ilogb_template.c
@@ -0,0 +1,30 @@
+#include <math.h>
+#include <errno.h>
+#include <limits.h>
+#include <math_private.h>
+#include <fenv.h>
+
+#if _GL_HAS_BUILTIN_ILOGB
+int
+M_DECL_FUNC (__ilogb) (FLOAT x)
+{
+ int r;
+ /* Check for exceptional cases. */
+ if (! M_SUF(__builtin_test_dc_ilogb) (x, 0x7f))
+ r = M_SUF (__builtin_ilogb) (x);
+ else
+ /* Fallback to the generic ilogb if x is NaN, Inf or subnormal. */
+ r = M_SUF (__ieee754_ilogb) (x);
+ if (__builtin_expect (r == FP_ILOGB0, 0)
+ || __builtin_expect (r == FP_ILOGBNAN, 0)
+ || __builtin_expect (r == INT_MAX, 0))
+ {
+ __set_errno (EDOM);
+ __feraiseexcept (FE_INVALID);
+ }
+ return r;
+}
+declare_mgen_alias (__ilogb, ilogb)
+#else
+#include <math/w_ilogb_template.c>
+#endif
diff --git a/sysdeps/powerpc/powerpc64/le/fpu/w_ilogbl.c b/sysdeps/powerpc/powerpc64/le/fpu/w_ilogbl.c
new file mode 100644
index 0000000000000000..205f154f0089a269
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/le/fpu/w_ilogbl.c
@@ -0,0 +1,4 @@
+/* Skip the optimization for long double as ibm128 does not provide an
+ optimized builtin. */
+#include <math-type-macros-ldouble.h>
+#include <math/w_ilogb_template.c>