[gcc(refs/users/meissner/heads/work018)] PowerPC: Update __float128 <-> __ibm128 conversion.

[gcc(refs/users/meissner/heads/work018)] PowerPC: Update __float128 <-> __ibm128 conversion.

[Michael Meissner]

https://gcc.gnu.org/g:c76ddd4c67e6b7865149fc12c0c2b91826c9b2d1

commit c76ddd4c67e6b7865149fc12c0c2b91826c9b2d1
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Fri Sep 18 14:11:24 2020 -0400

    PowerPC: Update __float128 <-> __ibm128 conversion.
    
    libgcc/
    2020-09-18  Michael Meissner  <meissner@linux.ibm.com>
    
            * config/rs6000/extendkftf2-sw.c: Move __float128 to __ibm128
            conversion into float128-convert.h.
            * config/rs6000/float128-convert.h: New file.
            * config/rs6000/float128-hw.c: Move conversions between __float128
            and __ibm128 into float128-convert.h.
            * config/rs6000/quad-float128.h: Move conversions between
            __float128 and __ibm128 into float128-convert.h.
            * config/rs6000/trunctfkf2-sw.c: Move __ibm128 to __float128
            conversion to float128-convert.h.

Diff:
---
 libgcc/config/rs6000/extendkftf2-sw.c   |  6 +--
 libgcc/config/rs6000/float128-convert.h | 77 +++++++++++++++++++++++++++++++++
 libgcc/config/rs6000/float128-hw.c      | 11 ++---
 libgcc/config/rs6000/quad-float128.h    | 58 -------------------------
 libgcc/config/rs6000/trunctfkf2-sw.c    |  6 +--
 5 files changed, 84 insertions(+), 74 deletions(-)

diff --git a/libgcc/config/rs6000/extendkftf2-sw.c b/libgcc/config/rs6000/extendkftf2-sw.c
index f0de1784c43..80b48c20d9c 100644
--- a/libgcc/config/rs6000/extendkftf2-sw.c
+++ b/libgcc/config/rs6000/extendkftf2-sw.c
@@ -38,6 +38,7 @@
 
 #include "soft-fp.h"
 #include "quad-float128.h"
+#include "float128-convert.h"
 
 #ifndef FLOAT128_HW_INSNS
 #define __extendkftf2_sw __extendkftf2
@@ -46,8 +47,5 @@
 IBM128_TYPE
 __extendkftf2_sw (TFtype value)
 {
-  IBM128_TYPE ret;
-
-  CVT_FLOAT128_TO_IBM128 (ret, value);
-  return ret;
+  return convert_float128_to_ibm128 (value);
 }
diff --git a/libgcc/config/rs6000/float128-convert.h b/libgcc/config/rs6000/float128-convert.h
new file mode 100644
index 00000000000..bb6b3d71889
--- /dev/null
+++ b/libgcc/config/rs6000/float128-convert.h
@@ -0,0 +1,77 @@
+/* Convert between IEEE 128-bit and IBM 128-bit floating point types.
+   Copyright (C) 2016-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Michael Meissner (meissner@linux.ibm.com).
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Implementation of conversions between __ibm128 and __float128, to allow the
+   same code to be used on systems with IEEE 128-bit emulation and with IEEE
+   128-bit hardware support.
+
+   These functions are called by the actual conversion functions called by the
+   compiler.  This code is here to allow being built at power8 (no hardware
+   float128) and power9 (hardware float128) varients that is selected by an
+   IFUNC function.  */
+
+static inline __ibm128 convert_float128_to_ibm128 (__float128);
+static inline __float128 convert_ibm128_to_float128 (__ibm128);
+
+static inline __ibm128
+convert_float128_to_ibm128 (__float128 value)
+{
+  double high, high_temp, low;
+
+  high = (double) value;
+  if (__builtin_isnan (high) || __builtin_isinf (high))
+    low = 0.0;
+
+  else
+    {
+      low = (double) (value - (__float128) high);
+      /* Renormalize low/high and move them into canonical IBM long
+	 double form.  */
+      high_temp = high + low;
+      low = (high - high_temp) + low;
+      high = high_temp;
+    }
+
+  return __builtin_pack_ibm128 (high, low);
+}
+
+static inline __float128
+convert_ibm128_to_float128 (__ibm128 value)
+{
+  double high = __builtin_unpack_ibm128 (value, 0);
+  double low = __builtin_unpack_ibm128 (value, 1);
+
+  /* Handle the special cases of NAN and infinity.  Similarly, if low is 0.0,
+     there no need to do the add.  In addition, avoiding the add produces the
+     correct sign if high is -0.0.  */
+  if (__builtin_isnan (high) || __builtin_isinf (high) || low == 0.0)
+    return (__float128) high;
+
+  else
+    return ((__float128) high) + ((__float128) low);
+}
diff --git a/libgcc/config/rs6000/float128-hw.c b/libgcc/config/rs6000/float128-hw.c
index 8705b53e22a..b9b04cd2feb 100644
--- a/libgcc/config/rs6000/float128-hw.c
+++ b/libgcc/config/rs6000/float128-hw.c
@@ -33,6 +33,7 @@
 
 #include <soft-fp.h>
 #include <quad-float128.h>
+#include "float128-convert.h"
 
 #ifndef __FLOAT128_HARDWARE__
 #error "This module must be compiled with IEEE 128-bit hardware support"
@@ -190,18 +191,12 @@ __unordkf2_hw (TFtype a, TFtype b)
 IBM128_TYPE
 __extendkftf2_hw (TFtype value)
 {
-  IBM128_TYPE ret;
-
-  CVT_FLOAT128_TO_IBM128 (ret, value);
-  return ret;
+  return convert_float128_to_ibm128 (value);
 }
 
 /* Convert __ibm128 to __float128.  */
 TFtype
 __trunctfkf2_hw (IBM128_TYPE value)
 {
-  TFtype ret;
-
-  CVT_IBM128_TO_FLOAT128 (ret, value);
-  return ret;
+  return convert_ibm128_to_float128 (value);
 }
diff --git a/libgcc/config/rs6000/quad-float128.h b/libgcc/config/rs6000/quad-float128.h
index 32ef328a8ea..15880c2ab30 100644
--- a/libgcc/config/rs6000/quad-float128.h
+++ b/libgcc/config/rs6000/quad-float128.h
@@ -170,61 +170,3 @@ extern TFtype __trunctfkf2 (IBM128_TYPE);
 /* Complex __float128 built on __float128 interfaces.  */
 extern TCtype __mulkc3 (TFtype, TFtype, TFtype, TFtype);
 extern TCtype __divkc3 (TFtype, TFtype, TFtype, TFtype);
-
-/* Implementation of conversions between __ibm128 and __float128, to allow the
-   same code to be used on systems with IEEE 128-bit emulation and with IEEE
-   128-bit hardware support.  */
-
-union ibm128_union {
-  IBM128_TYPE ibm128;
-  double dbl[2];
-};
-
-#define CVT_FLOAT128_TO_IBM128(RESULT, VALUE)				\
-{									\
-  double __high, __low;							\
-  TFtype __value = (VALUE);						\
-  union ibm128_union u;							\
-									\
-  __high = (double) __value;						\
-  if (__builtin_isnan (__high) || __builtin_isinf (__high))		\
-    __low = 0.0;							\
-									\
-  else									\
-    {									\
-      double __high_temp;						\
-									\
-      __low = (double) (__value - (TFtype) __high);			\
-      /* Renormalize low/high and move them into canonical IBM long	\
-	 double form.  */						\
-      __high_temp = __high + __low;					\
-      __low = (__high - __high_temp) + __low;				\
-      __high = __high_temp;						\
-    }									\
-									\
-  u.dbl[0] = __high;							\
-  u.dbl[1] = __low;							\
-  RESULT = u.ibm128;							\
-}
-
-#define CVT_IBM128_TO_FLOAT128(RESULT, VALUE)				\
-{									\
-  union ibm128_union u;							\
-  double __high, __low;							\
-									\
-  u.ibm128 = (VALUE);							\
-  __high = u.dbl[0];							\
-  __low = u.dbl[1];							\
-									\
-  /* Handle the special cases of NAN and infinity.  */			\
-  if (__builtin_isnan (__high) || __builtin_isinf (__high))		\
-    RESULT = (TFtype) __high;						\
-									\
-  /* If low is 0.0, there no need to do the add.  In addition,		\
-     avoiding the add produces the correct sign if high is -0.0.  */	\
-  else if (__low == 0.0)						\
-    RESULT = (TFtype) __high;						\
-									\
-  else									\
-    RESULT = ((TFtype) __high) + ((TFtype) __low);			\
-}
diff --git a/libgcc/config/rs6000/trunctfkf2-sw.c b/libgcc/config/rs6000/trunctfkf2-sw.c
index 3e8af25a585..af52cff5954 100644
--- a/libgcc/config/rs6000/trunctfkf2-sw.c
+++ b/libgcc/config/rs6000/trunctfkf2-sw.c
@@ -38,6 +38,7 @@
 
 #include "soft-fp.h"
 #include "quad-float128.h"
+#include "float128-convert.h"
 
 #ifndef FLOAT128_HW_INSNS
 #define __trunctfkf2_sw __trunctfkf2
@@ -46,8 +47,5 @@
 TFtype
 __trunctfkf2_sw (IBM128_TYPE value)
 {
-  TFtype ret;
-
-  CVT_IBM128_TO_FLOAT128 (ret, value);
-  return ret;
+  return convert_ibm128_to_float128 (value);
 }