rs6000: Allow -mlong-double-64 after -mabi={ibm,ieee}longdouble [PR104208, PR87496]

The glibc build is showing a build error due to extra "error" checking from my
PR87496 fix.  That checking was overeager, disallowing setting the long double
size to 64-bits if the 128-bit long double ABI had already been specified.
Now we only emit an error if we specify a 128-bit long double ABI if our
long double size is not 128 bits.  This also fixes an erroneous error when
-mabi=ieeelongdouble is used and ISA 2.06 is not enabled, but the long double
size has been changed to 64 bits.

2022-03-04  Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/87496
	PR target/104208
	* config/rs6000/rs6000.cc (rs6000_option_override_internal): Make the
	ISA 2.06 requirement for -mabi=ieeelongdouble conditional on
	-mlong-double-128.
	Move the -mabi=ieeelongdouble and -mabi=ibmlongdouble error checking
	from here...
	* common/config/rs6000/rs6000-common.cc (rs6000_handle_option):
	... to here.

gcc/testsuite/
	PR target/87496
	PR target/104208
	* gcc.target/powerpc/pr104208-1.c: New test.
	* gcc.target/powerpc/pr104208-2.c: Likewise.
	* gcc.target/powerpc/pr87496-2.c: Swap long double options to trigger
	the expected error.
	* gcc.target/powerpc/pr87496-3.c: Likewise.

6 files changed, 33 insertions, 11 deletions

diff --git a/gcc/common/config/rs6000/rs6000-common.cc b/gcc/common/config/rs6000/rs6000-common.cc
index 97dff3a..8e393d0 100644
--- a/gcc/common/config/rs6000/rs6000-common.cc
+++ b/gcc/common/config/rs6000/rs6000-common.cc
@@ -227,6 +227,16 @@ rs6000_handle_option (struct gcc_options *opts, struct gcc_options *opts_set,
 	}
       break;
 
+    case OPT_mabi_ibmlongdouble:
+    case OPT_mabi_ieeelongdouble:
+      if (opts->x_rs6000_long_double_type_size == 64)
+	{
+	  error_at (loc, "option %<%s%> requires %<-mlong-double-128%>",
+		    decoded->orig_option_with_args_text);
+	  return true;
+	}
+      break;
+
     case OPT_mrecip:
       opts->x_rs6000_recip_name = (value) ? "default" : "none";
       break;
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index a855e8c..5b100a8 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -4178,13 +4178,6 @@ rs6000_option_override_internal (bool global_init_p)
     ; /* The option value can be seen when cl_target_option_restore is called.  */
   else if (rs6000_long_double_type_size == 128)
     rs6000_long_double_type_size = FLOAT_PRECISION_TFmode;
-  else if (OPTION_SET_P (rs6000_ieeequad))
-    {
-      if (global_options.x_rs6000_ieeequad)
-	error ("%qs requires %qs", "-mabi=ieeelongdouble", "-mlong-double-128");
-      else
-	error ("%qs requires %qs", "-mabi=ibmlongdouble", "-mlong-double-128");
-    }
 
   /* 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
@@ -4194,13 +4187,13 @@ rs6000_option_override_internal (bool global_init_p)
   if (!OPTION_SET_P (rs6000_ieeequad))
     rs6000_ieeequad = TARGET_IEEEQUAD_DEFAULT;
 
-  else
+  else if (TARGET_LONG_DOUBLE_128)
     {
       if (global_options.x_rs6000_ieeequad
 	  && (!TARGET_POPCNTD || !TARGET_VSX))
 	error ("%qs requires full ISA 2.06 support", "-mabi=ieeelongdouble");
 
-      if (rs6000_ieeequad != TARGET_IEEEQUAD_DEFAULT && TARGET_LONG_DOUBLE_128)
+      if (rs6000_ieeequad != TARGET_IEEEQUAD_DEFAULT)
 	{
 	  /* Determine if the user can change the default long double type at
 	     compilation time.  You need GLIBC 2.32 or newer to be able to
diff --git a/gcc/testsuite/gcc.target/powerpc/pr104208-1.c b/gcc/testsuite/gcc.target/powerpc/pr104208-1.c
new file mode 100644
index 0000000..39d4602
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr104208-1.c
@@ -0,0 +1,9 @@
+/* PR target/104208 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mlong-double-128 -mabi=ibmlongdouble -mlong-double-64 -Wno-psabi" } */
+
+/* Verify we do not emit an error with the options above.  It is allowed
+   to reset the long double size to 64-bits after a 128-bit long double
+   ABI has been selected.  */
+
+int i;
diff --git a/gcc/testsuite/gcc.target/powerpc/pr104208-2.c b/gcc/testsuite/gcc.target/powerpc/pr104208-2.c
new file mode 100644
index 0000000..4e8ab5b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr104208-2.c
@@ -0,0 +1,10 @@
+/* PR target/104208 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mlong-double-128 -mabi=ieeelongdouble -mlong-double-64 -mno-vsx -Wno-psabi" } */
+
+/* Verify we do not emit an error with the options above.  IEEE 128-bit
+   long double requires VSX, so using -mno-vsx would normally generate
+   an error.  However, if we have changed to a 64-bit long double, then
+   we should allow it.  */
+
+int i;
diff --git a/gcc/testsuite/gcc.target/powerpc/pr87496-2.c b/gcc/testsuite/gcc.target/powerpc/pr87496-2.c
index 26c07eb..f9dc642 100644
--- a/gcc/testsuite/gcc.target/powerpc/pr87496-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/pr87496-2.c
@@ -1,7 +1,7 @@
 /* PR target/87496 */
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
-/* { dg-options "-O2 -mdejagnu-cpu=power7 -mabi=ieeelongdouble -mlong-double-64 -Wno-psabi" } */
+/* { dg-options "-O2 -mdejagnu-cpu=power7 -mlong-double-64 -mabi=ieeelongdouble -Wno-psabi" } */
 
 int i;
 
diff --git a/gcc/testsuite/gcc.target/powerpc/pr87496-3.c b/gcc/testsuite/gcc.target/powerpc/pr87496-3.c
index 1be3997..39fb73c 100644
--- a/gcc/testsuite/gcc.target/powerpc/pr87496-3.c
+++ b/gcc/testsuite/gcc.target/powerpc/pr87496-3.c
@@ -1,7 +1,7 @@
 /* PR target/87496 */
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
-/* { dg-options "-O2 -mabi=ibmlongdouble -mlong-double-64 -Wno-psabi" } */
+/* { dg-options "-O2 -mlong-double-64 -mabi=ibmlongdouble -Wno-psabi" } */
 
 int i;