aix.h (TARGET_IEEEQUAD_DEFAULT): Set long double default to IBM.

[gcc]
2017-10-26  Michael Meissner  <meissner@linux.vnet.ibm.com>

	* config/rs6000/aix.h (TARGET_IEEEQUAD_DEFAULT): Set long double
	default to IBM.
	* config/rs6000/darwin.h (TARGET_IEEEQUAD_DEFAULT): Likewise.
	* config/rs6000/rs6000.opt (-mabi=ieeelongdouble): Move the
	warning to rs6000.c.  Remove the Undocumented flag, since it has
	been documented.
	(-mabi=ibmlongdouble): Likewise.
	* config/rs6000/rs6000.c (TARGET_IEEEQUAD_DEFAULT): If it is not
	already set, set the default format for long double.
	(rs6000_debug_reg_global): Print whether long double is IBM or
	IEEE.
	(rs6000_option_override_internal): Rework setting long double
	format.  Only warn if the user is changing the long double default
	and they did not use -Wno-psabi.
	* doc/invoke.texi (PowerPC options): Update the documentation for
	-mabi=ieeelongdouble and -mabi=ibmlongdouble.

From-SVN: r254116

6 files changed, 75 insertions, 10 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4312ac2..c6e0b85 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,22 @@
+2017-10-26  Michael Meissner  <meissner@linux.vnet.ibm.com>
+
+	* config/rs6000/aix.h (TARGET_IEEEQUAD_DEFAULT): Set long double
+	default to IBM.
+	* config/rs6000/darwin.h (TARGET_IEEEQUAD_DEFAULT): Likewise.
+	* config/rs6000/rs6000.opt (-mabi=ieeelongdouble): Move the
+	warning to rs6000.c.  Remove the Undocumented flag, since it has
+	been documented.
+	(-mabi=ibmlongdouble): Likewise.
+	* config/rs6000/rs6000.c (TARGET_IEEEQUAD_DEFAULT): If it is not
+	already set, set the default format for long double.
+	(rs6000_debug_reg_global): Print whether long double is IBM or
+	IEEE.
+	(rs6000_option_override_internal): Rework setting long double
+	format.  Only warn if the user is changing the long double default
+	and they did not use -Wno-psabi.
+	* doc/invoke.texi (PowerPC options): Update the documentation for
+	-mabi=ieeelongdouble and -mabi=ibmlongdouble.
+
 2017-10-26  Richard Sandiford  <richard.sandiford@linaro.org>
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
diff --git a/gcc/config/rs6000/aix.h b/gcc/config/rs6000/aix.h
index 607b42c..7354181 100644
--- a/gcc/config/rs6000/aix.h
+++ b/gcc/config/rs6000/aix.h
@@ -76,6 +76,9 @@
 #undef  TARGET_IEEEQUAD
 #define TARGET_IEEEQUAD 0
 
+#undef  TARGET_IEEEQUAD_DEFAULT
+#define TARGET_IEEEQUAD_DEFAULT 0
+
 /* The AIX linker will discard static constructors in object files before
    collect has a chance to see them, so scan the object files directly.  */
 #define COLLECT_EXPORT_LIST
diff --git a/gcc/config/rs6000/darwin.h b/gcc/config/rs6000/darwin.h
index 9a88a8d..a6a7b2c 100644
--- a/gcc/config/rs6000/darwin.h
+++ b/gcc/config/rs6000/darwin.h
@@ -272,6 +272,9 @@ extern int darwin_emit_branch_islands;
 #undef  TARGET_IEEEQUAD
 #define TARGET_IEEEQUAD 0
 
+#undef  TARGET_IEEEQUAD_DEFAULT
+#define TARGET_IEEEQUAD_DEFAULT 0
+
 /* Since Darwin doesn't do TOCs, stub this out.  */
 
 #define ASM_OUTPUT_SPECIAL_POOL_ENTRY_P(X, MODE)  ((void)X, (void)MODE, 0)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 3095419..3162d52 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -86,6 +86,20 @@
 #define TARGET_NO_PROTOTYPE 0
 #endif
 
+  /* Set -mabi=ieeelongdouble on some old targets.  In the future, power server
+     systems will also set long double to be IEEE 128-bit.  AIX and Darwin
+     explicitly redefine TARGET_IEEEQUAD and TARGET_IEEEQUAD_DEFAULT to 0, so
+     those systems will not pick up this default.  This needs to be after all
+     of the include files, so that POWERPC_LINUX and POWERPC_FREEBSD are
+     properly defined.  */
+#ifndef TARGET_IEEEQUAD_DEFAULT
+#if !defined (POWERPC_LINUX) && !defined (POWERPC_FREEBSD)
+#define TARGET_IEEEQUAD_DEFAULT 1
+#else
+#define TARGET_IEEEQUAD_DEFAULT 0
+#endif
+#endif
+
 #define min(A,B)	((A) < (B) ? (A) : (B))
 #define max(A,B)	((A) > (B) ? (A) : (B))
 
@@ -2878,6 +2892,13 @@ rs6000_debug_reg_global (void)
   fprintf (stderr, DEBUG_FMT_D, "tls_size", rs6000_tls_size);
   fprintf (stderr, DEBUG_FMT_D, "long_double_size",
 	   rs6000_long_double_type_size);
+  if (rs6000_long_double_type_size == 128)
+    {
+      fprintf (stderr, DEBUG_FMT_S, "long double type",
+	       TARGET_IEEEQUAD ? "IEEE" : "IBM");
+      fprintf (stderr, DEBUG_FMT_S, "default long double type",
+	       TARGET_IEEEQUAD_DEFAULT ? "IEEE" : "IBM");
+    }
   fprintf (stderr, DEBUG_FMT_D, "sched_restricted_insns_priority",
 	   (int)rs6000_sched_restricted_insns_priority);
   fprintf (stderr, DEBUG_FMT_D, "Number of standard builtins",
@@ -4560,13 +4581,26 @@ rs6000_option_override_internal (bool global_init_p)
 	rs6000_long_double_type_size = RS6000_DEFAULT_LONG_DOUBLE_SIZE;
     }
 
-  /* Set -mabi=ieeelongdouble on some old targets.  Note, AIX and Darwin
-     explicitly redefine TARGET_IEEEQUAD to 0, so those systems will not
-     pick up this default.  */
-#if !defined (POWERPC_LINUX) && !defined (POWERPC_FREEBSD)
+  /* Set -mabi=ieeelongdouble on some old targets.  In the future, power server
+     systems will also set long double to be IEEE 128-bit.  AIX and Darwin
+     explicitly redefine TARGET_IEEEQUAD and TARGET_IEEEQUAD_DEFAULT to 0, so
+     those systems will not pick up this default.  Warn if the user changes the
+     default unless -Wno-psabi.  */
   if (!global_options_set.x_rs6000_ieeequad)
-    rs6000_ieeequad = 1;
-#endif
+    rs6000_ieeequad = TARGET_IEEEQUAD_DEFAULT;
+
+  else if (rs6000_ieeequad != TARGET_IEEEQUAD_DEFAULT && TARGET_LONG_DOUBLE_128)
+    {
+      static bool warned_change_long_double;
+      if (!warned_change_long_double)
+	{
+	  warned_change_long_double = true;
+	  if (TARGET_IEEEQUAD)
+	    warning (OPT_Wpsabi, "Using IEEE extended precision long double");
+	  else
+	    warning (OPT_Wpsabi, "Using IBM extended precision long double");
+	}
+    }
 
   /* Enable the default support for IEEE 128-bit floating point on Linux VSX
      sytems.  In GCC 7, we would enable the the IEEE 128-bit floating point
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index c42818f..e7d0829 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -381,10 +381,10 @@ mabi=d32
 Target RejectNegative Undocumented Warn(using old darwin ABI) Var(rs6000_darwin64_abi, 0)
 
 mabi=ieeelongdouble
-Target RejectNegative Undocumented Warn(using IEEE extended precision long double) Var(rs6000_ieeequad) Save
+Target RejectNegative Var(rs6000_ieeequad) Save
 
 mabi=ibmlongdouble
-Target RejectNegative Undocumented Warn(using IBM extended precision long double) Var(rs6000_ieeequad, 0)
+Target RejectNegative Var(rs6000_ieeequad, 0)
 
 mcpu=
 Target RejectNegative Joined Var(rs6000_cpu_index) Init(-1) Enum(rs6000_cpu_opt_value) Save
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 71b2445..f950c3c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -22614,12 +22614,18 @@ Disable Book-E SPE ABI extensions for the current ABI@.
 @item -mabi=ibmlongdouble
 @opindex mabi=ibmlongdouble
 Change the current ABI to use IBM extended-precision long double.
-This is a PowerPC 32-bit SYSV ABI option.
+This is not likely to work if your system defaults to using IEEE
+extended-precision long double.  If you change the long double type
+from IEEE extended-precision, the compiler will issue a warning unless
+you use the @option{-Wno-psabi} option.
 
 @item -mabi=ieeelongdouble
 @opindex mabi=ieeelongdouble
 Change the current ABI to use IEEE extended-precision long double.
-This is a PowerPC 32-bit Linux ABI option.
+This is not likely to work if your system defaults to using IBM
+extended-precision long double.  If you change the long double type
+from IBM extended-precision, the compiler will issue a warning unless
+you use the @option{-Wno-psabi} option.
 
 @item -mabi=elfv1
 @opindex mabi=elfv1