[PATCH 1/5] IEEE 128-bit built-in overload support.

[Michael Meissner <meissner@linux.ibm.com>]

[PATCH 1/5] IEEE 128-bit built-in overload support.

This patch lays the ground work that future patches will use to add
builtin support (both normal and overloaded) for the case where long
double uses the IEEE 128-bit encoding.

This adds a new stanza (ieee128-hw-ld) for when we have IEEE 128-bit
hardware support and long double uses the IEEE 128-bit encoding.

A new type attribute (ieeeld) is added for long double if long double uses
the IEEE 128-bit encoding.

I have tested these patches on a power10 that is running Fedora 36, which
defaults to using long doubles that are IEEE 128-bit.  I have built two
parallel GCC compilers, one that defaults to using IEEE 128-bit long doubles
and one that defaults to using IBM 128-bit long doubles.

I have compared the test results to the original compiler results, comparing a
modified GCC to the original compiler using an IEEE 128-bit long double
default, and also comparing a modified GCC to the original compiler using an
IBM 128-bit long double default.  In both cases, the results are the same.

I have also compared the compilers with the future patch in progress that does
switch the internal type handling.  Once those patches are installed, the
overload mechanism will insure the correct built-in is used.

Can I install this patch to the trunk?

2022-07-27   Michael Meissner  <meissner@linux.ibm.com>

gcc/

	* config/rs6000/rs6000-builtin.cc (rs6000_invalid_builtin): Add
	support for ibm128-hw-ld stanza.
	(rs6000_builtin_is_supported): Likewise.
	(rs6000_init_builtins): Likewise.
	(rs6000_expand_builtin): Add support for IEEE128_HW_LD.  Add
	support for ieeeld.
	* config/rs6000/rs6000-builtins.def (toplevel): Add comment about
	the new ieeeld attribute.
	* config/rs6000/rs6000-gen-builtins.cc (enum bif_stanza): Add
	BSTZ_IEEE128_HW_LD.
	(stanza_map): Likewise.
	(enable_string): Likewise.
	(attrinfo): Add isieeeld.
	(parse_bif_attrs): Parse ieeeld.  Add printing ieeeld to the debug
	print.
	(write_decls): Add support for ibm128-hw-ld stanza and ieeeld
	attribute.
	(write_bif_static_init): Add support for ieeeld attribute.
---
 gcc/config/rs6000/rs6000-builtin.cc      | 18 ++++++++++++++++++
 gcc/config/rs6000/rs6000-builtins.def    |  1 +
 gcc/config/rs6000/rs6000-gen-builtins.cc | 18 ++++++++++++++++--
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/gcc/config/rs6000/rs6000-builtin.cc b/gcc/config/rs6000/rs6000-builtin.cc
index 2819773d9f9..67e86bee781 100644
--- a/gcc/config/rs6000/rs6000-builtin.cc
+++ b/gcc/config/rs6000/rs6000-builtin.cc
@@ -123,6 +123,10 @@ rs6000_invalid_builtin (enum rs6000_gen_builtins fncode)
     case ENB_IEEE128_HW:
       error ("%qs requires quad-precision floating-point arithmetic", name);
       break;
+    case ENB_IEEE128_HW_LD:
+      error ("%qs requires %qs to use IEEE quad-precision floating-point "
+	     "arithmetic", name, "long double");
+      break;
     case ENB_DFP:
       error ("%qs requires the %qs option", name, "-mhard-dfp");
       break;
@@ -189,6 +193,8 @@ rs6000_builtin_is_supported (enum rs6000_gen_builtins fncode)
       return TARGET_ALTIVEC && rs6000_cpu == PROCESSOR_CELL;
     case ENB_IEEE128_HW:
       return TARGET_FLOAT128_HW;
+    case ENB_IEEE128_HW_LD:
+      return TARGET_FLOAT128_HW && FLOAT128_IEEE_P (TFmode);
     case ENB_DFP:
       return TARGET_DFP;
     case ENB_CRYPTO:
@@ -857,6 +863,9 @@ rs6000_init_builtins (void)
 	    continue;
 	  if (e == ENB_IEEE128_HW && !TARGET_FLOAT128_HW)
 	    continue;
+	  if (e == ENB_IEEE128_HW_LD && (!TARGET_FLOAT128_HW
+					 || !FLOAT128_IEEE_P (TFmode)))
+	    continue;
 	  if (e == ENB_DFP && !TARGET_DFP)
 	    continue;
 	  if (e == ENB_CRYPTO && !TARGET_CRYPTO)
@@ -3387,6 +3396,8 @@ rs6000_expand_builtin (tree exp, rtx target, rtx /* subtarget */,
 	|| (e == ENB_P9_64 && TARGET_MODULO && TARGET_POWERPC64)
 	|| (e == ENB_P9V && TARGET_P9_VECTOR)
 	|| (e == ENB_IEEE128_HW && TARGET_FLOAT128_HW)
+	|| (e == ENB_IEEE128_HW_LD && TARGET_FLOAT128_HW
+	    && FLOAT128_IEEE_P (TFmode))
 	|| (e == ENB_DFP && TARGET_DFP)
 	|| (e == ENB_CRYPTO && TARGET_CRYPTO)
 	|| (e == ENB_HTM && TARGET_HTM)
@@ -3426,6 +3437,13 @@ rs6000_expand_builtin (tree exp, rtx target, rtx /* subtarget */,
       return const0_rtx;
     }
 
+  if (bif_is_ieeeld (*bifaddr) && !FLOAT128_IEEE_P (TFmode))
+    {
+      error ("%qs requires %<long double%> to be IEEE 128-bit format",
+	     bifaddr->bifname);
+      return const0_rtx;
+    }
+
   if (bif_is_cpu (*bifaddr))
     return cpu_expand_builtin (fcode, exp, target);
 
diff --git a/gcc/config/rs6000/rs6000-builtins.def b/gcc/config/rs6000/rs6000-builtins.def
index f76f54793d7..defd7e25ffe 100644
--- a/gcc/config/rs6000/rs6000-builtins.def
+++ b/gcc/config/rs6000/rs6000-builtins.def
@@ -139,6 +139,7 @@
 ;   endian   Needs special handling for endianness
 ;   ibmld    Restrict usage to the case when TFmode is IBM-128
 ;   ibm128   Restrict usage to the case where __ibm128 is supported or if ibmld
+;   ieeeld   Restrict usage to the case when TFmode is IEEE-128
 ;
 ; Each attribute corresponds to extra processing required when
 ; the built-in is expanded.  All such special processing should
diff --git a/gcc/config/rs6000/rs6000-gen-builtins.cc b/gcc/config/rs6000/rs6000-gen-builtins.cc
index 0bd7a535e5f..b939e04c258 100644
--- a/gcc/config/rs6000/rs6000-gen-builtins.cc
+++ b/gcc/config/rs6000/rs6000-gen-builtins.cc
@@ -95,6 +95,7 @@ along with GCC; see the file COPYING3.  If not see
      ibmld    Restrict usage to the case when TFmode is IBM-128
      ibm128   Restrict usage to the case where __ibm128 is supported or
               if ibmld
+     ieeeld   Restrict usage to the case when TFmode is IEEE-128
 
    An example stanza might look like this:
 
@@ -227,6 +228,7 @@ enum bif_stanza
  BSTZ_P9_64,
  BSTZ_P9V,
  BSTZ_IEEE128_HW,
+ BSTZ_IEEE128_HW_LD,
  BSTZ_DFP,
  BSTZ_CRYPTO,
  BSTZ_HTM,
@@ -261,6 +263,7 @@ static stanza_entry stanza_map[NUMBIFSTANZAS] =
     { "power9-64",	BSTZ_P9_64	},
     { "power9-vector",	BSTZ_P9V	},
     { "ieee128-hw",	BSTZ_IEEE128_HW	},
+    { "ieee128-hw-ld",	BSTZ_IEEE128_HW_LD },
     { "dfp",		BSTZ_DFP	},
     { "crypto",		BSTZ_CRYPTO	},
     { "htm",		BSTZ_HTM	},
@@ -286,6 +289,7 @@ static const char *enable_string[NUMBIFSTANZAS] =
     "ENB_P9_64",
     "ENB_P9V",
     "ENB_IEEE128_HW",
+    "ENB_IEEE128_HW_LD",
     "ENB_DFP",
     "ENB_CRYPTO",
     "ENB_HTM",
@@ -395,6 +399,7 @@ struct attrinfo
   bool isendian;
   bool isibmld;
   bool isibm128;
+  bool isieeeld;
 };
 
 /* Fields associated with a function prototype (bif or overload).  */
@@ -1444,6 +1449,8 @@ parse_bif_attrs (attrinfo *attrptr)
 	  attrptr->isibmld = 1;
 	else if (!strcmp (attrname, "ibm128"))
 	  attrptr->isibm128 = 1;
+	else if (!strcmp (attrname, "ieeeld"))
+	  attrptr->isieeeld = 1;
 	else
 	  {
 	    diag (oldpos, "unknown attribute.\n");
@@ -1477,7 +1484,8 @@ parse_bif_attrs (attrinfo *attrptr)
 	"ldvec = %d, stvec = %d, reve = %d, pred = %d, htm = %d, "
 	"htmspr = %d, htmcr = %d, mma = %d, quad = %d, pair = %d, "
 	"mmaint = %d, no32bit = %d, 32bit = %d, cpu = %d, ldstmask = %d, "
-	"lxvrse = %d, lxvrze = %d, endian = %d, ibmdld = %d, ibm128 = %d.\n",
+	"lxvrse = %d, lxvrze = %d, endian = %d, ibmdld = %d, ibm128 = %d, "
+	"ieeeld = %d.\n",
 	attrptr->isinit, attrptr->isset, attrptr->isextract,
 	attrptr->isnosoft, attrptr->isldvec, attrptr->isstvec,
 	attrptr->isreve, attrptr->ispred, attrptr->ishtm, attrptr->ishtmspr,
@@ -1485,7 +1493,7 @@ parse_bif_attrs (attrinfo *attrptr)
 	attrptr->ismmaint, attrptr->isno32bit, attrptr->is32bit,
 	attrptr->iscpu, attrptr->isldstmask, attrptr->islxvrse,
 	attrptr->islxvrze, attrptr->isendian, attrptr->isibmld,
-	attrptr->isibm128);
+	attrptr->isibm128, attrptr->isieeeld);
 #endif
 
   return PC_OK;
@@ -2252,6 +2260,7 @@ write_decls (void)
   fprintf (header_file, "  ENB_P9_64,\n");
   fprintf (header_file, "  ENB_P9V,\n");
   fprintf (header_file, "  ENB_IEEE128_HW,\n");
+  fprintf (header_file, "  ENB_IEEE128_HW_LD,\n");
   fprintf (header_file, "  ENB_DFP,\n");
   fprintf (header_file, "  ENB_CRYPTO,\n");
   fprintf (header_file, "  ENB_HTM,\n");
@@ -2301,6 +2310,7 @@ write_decls (void)
   fprintf (header_file, "#define bif_endian_bit\t\t(0x00200000)\n");
   fprintf (header_file, "#define bif_ibmld_bit\t\t(0x00400000)\n");
   fprintf (header_file, "#define bif_ibm128_bit\t\t(0x00800000)\n");
+  fprintf (header_file, "#define bif_ieeeld_bit\t\t(0x01000000)\n");
   fprintf (header_file, "\n");
   fprintf (header_file,
 	   "#define bif_is_init(x)\t\t((x).bifattrs & bif_init_bit)\n");
@@ -2350,6 +2360,8 @@ write_decls (void)
 	   "#define bif_is_ibmld(x)\t((x).bifattrs & bif_ibmld_bit)\n");
   fprintf (header_file,
 	   "#define bif_is_ibm128(x)\t((x).bifattrs & bif_ibm128_bit)\n");
+  fprintf (header_file,
+	   "#define bif_is_ieeeld(x)\t((x).bifattrs & bif_ieeeld_bit)\n");
   fprintf (header_file, "\n");
 
   fprintf (header_file,
@@ -2548,6 +2560,8 @@ write_bif_static_init (void)
 	fprintf (init_file, " | bif_ibmld_bit");
       if (bifp->attrs.isibm128)
 	fprintf (init_file, " | bif_ibm128_bit");
+      if (bifp->attrs.isieeeld)
+	fprintf (init_file, " | bif_ieeeld_bit");
       fprintf (init_file, ",\n");
       fprintf (init_file, "      /* restr_opnd */\t{%d, %d, %d},\n",
 	       bifp->proto.restr_opnd[0], bifp->proto.restr_opnd[1],
-- 
2.35.3


-- 
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: meissner@linux.ibm.com