nios2: Add -mcustom-fpu-cfg=fph2

The new -mcustom-fpu-cfg=fph2 option variant is useful to build a
multilib for the "Nios II Floating Point Hardware 2 Component":

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/ug/ug_nios2_custom_instruction.pdf

Directly using the corresponding -mcustom-insn=N options for this
floating-point unit leads to a combinatorial explosion in the potential
count of multilibs which may break the build.

gcc/

	* config/nios2/nios2.c (NIOS2_FPU_CONFIG_NUM): Adjust value.
	(nios2_init_fpu_configs): Provide register values for new
	-mcustom-fpu-cfg=fph2 option variant.
	* doc/invoke.texi (-mcustom-fpu-cfg=fph2): Document new option
	variant.

2 files changed, 50 insertions, 1 deletions

diff --git a/gcc/config/nios2/nios2.c b/gcc/config/nios2/nios2.c
index e4349e7..3ff4ff1 100644
--- a/gcc/config/nios2/nios2.c
+++ b/gcc/config/nios2/nios2.c
@@ -1208,7 +1208,7 @@ struct nios2_fpu_config
   int code[n2fpu_code_num];
 };
 
-#define NIOS2_FPU_CONFIG_NUM 3
+#define NIOS2_FPU_CONFIG_NUM 4
 static struct nios2_fpu_config custom_fpu_config[NIOS2_FPU_CONFIG_NUM];
 
 static void
@@ -1252,6 +1252,27 @@ nios2_init_fpu_configs (void)
   cfg->code[n2fpu_fsubs]   = 254;
   cfg->code[n2fpu_fdivs]   = 255;
 
+  NEXT_FPU_CONFIG;
+  cfg->name = "fph2";
+  cfg->code[n2fpu_fabss]   = 224;
+  cfg->code[n2fpu_fnegs]   = 225;
+  cfg->code[n2fpu_fcmpnes] = 226;
+  cfg->code[n2fpu_fcmpeqs] = 227;
+  cfg->code[n2fpu_fcmpges] = 228;
+  cfg->code[n2fpu_fcmpgts] = 229;
+  cfg->code[n2fpu_fcmples] = 230;
+  cfg->code[n2fpu_fcmplts] = 231;
+  cfg->code[n2fpu_fmaxs]   = 232;
+  cfg->code[n2fpu_fmins]   = 233;
+  cfg->code[n2fpu_round]   = 248;
+  cfg->code[n2fpu_fixsi]   = 249;
+  cfg->code[n2fpu_floatis] = 250;
+  cfg->code[n2fpu_fsqrts]  = 251;
+  cfg->code[n2fpu_fmuls]   = 252;
+  cfg->code[n2fpu_fadds]   = 253;
+  cfg->code[n2fpu_fsubs]   = 254;
+  cfg->code[n2fpu_fdivs]   = 255;
+
 #undef NEXT_FPU_CONFIG
   gcc_assert (i == NIOS2_FPU_CONFIG_NUM);
 }
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8f10091..3f30230 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -26121,6 +26121,26 @@ Currently, the following sets are defined:
 -mcustom-fdivs=255 @gol
 -fsingle-precision-constant}
 
+@option{-mcustom-fpu-cfg=fph2} is equivalent to:
+@gccoptlist{-mcustom-fabss=224 @gol
+-mcustom-fnegs=225 @gol
+-mcustom-fcmpnes=226 @gol
+-mcustom-fcmpeqs=227 @gol
+-mcustom-fcmpges=228 @gol
+-mcustom-fcmpgts=229 @gol
+-mcustom-fcmples=230 @gol
+-mcustom-fcmplts=231 @gol
+-mcustom-fmaxs=232 @gol
+-mcustom-fmins=233 @gol
+-mcustom-round=248 @gol
+-mcustom-fixsi=249 @gol
+-mcustom-floatis=250 @gol
+-mcustom-fsqrts=251 @gol
+-mcustom-fmuls=252 @gol
+-mcustom-fadds=253 @gol
+-mcustom-fsubs=254 @gol
+-mcustom-fdivs=255 @gol}
+
 Custom instruction assignments given by individual
 @option{-mcustom-@var{insn}=} options override those given by
 @option{-mcustom-fpu-cfg=}, regardless of the
@@ -26131,6 +26151,14 @@ configuration by using the @code{target("custom-fpu-cfg=@var{name}")}
 function attribute (@pxref{Function Attributes})
 or pragma (@pxref{Function Specific Option Pragmas}).
 
+The name @var{fph2} is an abbreviation for @emph{Nios II Floating Point
+Hardware 2 Component}.  Please note that the custom instructions enabled by
+@option{-mcustom-fmins=233} and @option{-mcustom-fmaxs=234} are only generated
+if @option{-ffinite-math-only} is specified.  The custom instruction enabled by
+@option{-mcustom-round=248} is only generated if @option{-fno-math-errno} is
+specified.  In contrast to the other configurations,
+@option{-fsingle-precision-constant} is not set.
+
 @end table
 
 These additional @samp{-m} options are available for the Altera Nios II