nios2: Remove custom instruction warnings

Do not warn if custom instructions are not used due to missing
optimization flags.  This prevents build errors with -Werror which
cannot be disabled via a dedicated warning option.

One reason to remove these warnings is to enable a multilib for the
"Nios II Floating Point Hardware 2 Component".  For example, the
libatomic target library in GCC is built with -Werror and the warnings
removed by this patch resulted in errors like:

cc1: error: switch '-mcustom-fmins' has no effect unless '-ffinite-math-only' is specified [-Werror]
cc1: error: switch '-mcustom-fmaxs' has no effect unless '-ffinite-math-only' is specified [-Werror]
cc1: error: switch '-mcustom-round' has no effect unless '-fno-math-errno' is specified [-Werror]

gcc/

	* config/nios2/nios2.c (nios2_custom_check_insns): Remove
	custom instruction warnings.

1 files changed, 0 insertions, 28 deletions

diff --git a/gcc/config/nios2/nios2.c b/gcc/config/nios2/nios2.c
index 3bffabe..e4349e7 100644
--- a/gcc/config/nios2/nios2.c
+++ b/gcc/config/nios2/nios2.c
@@ -1186,34 +1186,6 @@ nios2_custom_check_insns (void)
 	break;
       }
 
-  /* Warn if the user has certain exotic operations that won't get used
-     without -funsafe-math-optimizations.  See expand_builtin () in
-     builtins.c.  */
-  if (!flag_unsafe_math_optimizations)
-    for (i = 0; i < ARRAY_SIZE (nios2_fpu_insn); i++)
-      if (N2FPU_ENABLED_P (i) && N2FPU_UNSAFE_P (i))
-	warning (0, "switch %<-mcustom-%s%> has no effect unless "
-		 "%<-funsafe-math-optimizations%> is specified",
-		 N2FPU_NAME (i));
-
-  /* Warn if the user is trying to use -mcustom-fmins et. al, that won't
-     get used without -ffinite-math-only.  See fold_builtin_fmin_fmax ()
-     in builtins.c.  */
-  if (!flag_finite_math_only)
-    for (i = 0; i < ARRAY_SIZE (nios2_fpu_insn); i++)
-      if (N2FPU_ENABLED_P (i) && N2FPU_FINITE_P (i))
-	warning (0, "switch %<-mcustom-%s%> has no effect unless "
-		 "%<-ffinite-math-only%> is specified", N2FPU_NAME (i));
-
-  /* Warn if the user is trying to use a custom rounding instruction
-     that won't get used without -fno-math-errno.  See
-     expand_builtin_int_roundingfn_2 () in builtins.c.  */
-  if (flag_errno_math)
-    for (i = 0; i < ARRAY_SIZE (nios2_fpu_insn); i++)
-      if (N2FPU_ENABLED_P (i) && N2FPU_NO_ERRNO_P (i))
-	warning (0, "switch %<-mcustom-%s%> has no effect unless "
-		 "%<-fno-math-errno%> is specified", N2FPU_NAME (i));
-
   if (errors || custom_code_conflict)
     fatal_error (input_location,
 		 "conflicting use of %<-mcustom%> switches, target attributes, "