From: Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
To: libc-alpha@sourceware.org
Cc: murphyp@linux.ibm.com, tuliom@linux.ibm.com,
Raphael Moreira Zinsly <rzinsly@linux.ibm.com>
Subject: [PATCH v2 1/3] powerpc: Add optimized ilogb* for POWER9
Date: Mon, 1 Mar 2021 14:51:38 -0300 [thread overview]
Message-ID: <20210301175140.29109-1-rzinsly@linux.ibm.com> (raw)
Changes since v1:
- Move the builtins definitions to powerpc's math_private.h.
- Check if the correct GCC version is used.
--8<---
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.
---
sysdeps/powerpc/fpu/math_private.h | 20 +++++++++++-
.../powerpc64/le/fpu/w_ilogb_template.c | 31 +++++++++++++++++++
2 files changed, 50 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/powerpc/powerpc64/le/fpu/w_ilogb_template.c
diff --git a/sysdeps/powerpc/fpu/math_private.h b/sysdeps/powerpc/fpu/math_private.h
index 91b1361749..accc28d091 100644
--- a/sysdeps/powerpc/fpu/math_private.h
+++ b/sysdeps/powerpc/fpu/math_private.h
@@ -25,7 +25,23 @@
#include_next <math_private.h>
-#if defined _ARCH_PWR9 && __HAVE_DISTINCT_FLOAT128
+#ifdef _ARCH_PWR9
+
+#define __builtin_test_dc_ilogbf __builtin_test_dc_ilogb
+#define __builtin_ilogbf __builtin_ilogb
+
+#define __builtin_test_dc_ilogbl __builtin_test_dc_ilogbf128
+#define __builtin_ilogbl __builtin_ilogbf128
+
+#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)
{
@@ -35,4 +51,6 @@ __ieee754_sqrtf128 (_Float128 __x)
}
#endif
+#endif /* _ARCH_PWR9 */
+
#endif /* _PPC_MATH_PRIVATE_H_ */
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 0000000000..17ac7809e1
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/le/fpu/w_ilogb_template.c
@@ -0,0 +1,31 @@
+/* The builtins used are only available with GCC 8.0 or newer. */
+#if defined _ARCH_PWR9 && __GNUC_PREREQ (8, 0)
+#include <math.h>
+#include <errno.h>
+#include <limits.h>
+#include <math_private.h>
+#include <fenv.h>
+
+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
--
2.29.2
next reply other threads:[~2021-03-01 17:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 17:51 Raphael Moreira Zinsly [this message]
2021-03-01 17:51 ` [PATCH v2 2/3] powerpc: Add optimized llogb* " Raphael Moreira Zinsly
2021-03-01 17:51 ` [PATCH v2 3/3] benchtests: Add ilogb* tests Raphael Moreira Zinsly
2021-03-02 1:27 ` [PATCH v2 1/3] powerpc: Add optimized ilogb* for POWER9 Paul A. Clarke
2021-03-03 16:23 ` Raphael M Zinsly
2021-03-03 17:20 ` Paul A. Clarke
2021-03-02 17:46 ` Paul E Murphy
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