* gensupport.c: Include hashtab.h.

	(insn_elision, condition_table, hash_c_test, cmp_c_test,
	maybe_eval_c_test): New routines and data structures to
	support insn elision.
	(init_md_reader): Read and initialize the condition_table.
	(read_md_rtx): Discard insn patterns whose C test is provably
	always false.
	* gensupport.h: Declare new functions and data structures.

	* genconditions.c, dummy-conditions.c: New files.
	* Makefile.in: Build genconditions; run it to construct
	insn-conditions.c; build that and link it into most gen*
	programs.
	(HOST_SUPPORT, HOST_EARLY_SUPPORT): New variables.
	(GEN): Delete, unused.
	(STAGESTUFF): Update.

	* gencodes.c: (gen_insn): #define CODE_FOR_xxx equal to
	CODE_FOR_nothing for all elided patterns.
	(main): Tweaked to support this.
	* genflags.c (gen_proto): Emit a static inline generator
	function here for all elided patterns, which simply returns
	NULL_RTX.
	(gen_insn): Do not define HAVE_xxx for elided patterns.
	(main): Tweaked to support this.  No need to forward-declare
	struct rtx_def.
	* genrecog.c: Do not bother emitting the C test if it's known
	to be true at compile time.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@55839 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 18 insertions, 6 deletions

diff --git a/gcc/gencodes.c b/gcc/gencodes.c
index 0611eecaf03..5a292821c39 100644
--- a/gcc/gencodes.c
+++ b/gcc/gencodes.c
@@ -28,18 +28,26 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "errors.h"
 #include "gensupport.h"
 
-static void gen_insn PARAMS ((const char *, int));
+static void gen_insn PARAMS ((rtx, int));
 
 static void
-gen_insn (name, code)
-     const char *name;
+gen_insn (insn, code)
+     rtx insn;
      int code;
 {
+  const char *name = XSTR (insn, 0);
+  int truth = maybe_eval_c_test (XSTR (insn, 2));
+
   /* Don't mention instructions whose names are the null string
      or begin with '*'.  They are in the machine description just
      to be recognized.  */
   if (name[0] != 0 && name[0] != '*')
-    printf ("  CODE_FOR_%s = %d,\n", name, code);
+    {
+      if (truth == 0)
+	printf ("#define CODE_FOR_%s CODE_FOR_nothing\n", name);
+      else
+	printf ("  CODE_FOR_%s = %d,\n", name, code);
+    }
 }
 
 extern int main PARAMS ((int, char **));
@@ -53,6 +61,10 @@ main (argc, argv)
 
   progname = "gencodes";
 
+  /* We need to see all the possibilities.  Elided insns may have
+     direct references to CODE_FOR_xxx in C code.  */
+  insn_elision = 0;
+
   if (argc <= 1)
     fatal ("no input file name");
 
@@ -80,10 +92,10 @@ enum insn_code {");
 	break;
 
       if (GET_CODE (desc) == DEFINE_INSN || GET_CODE (desc) == DEFINE_EXPAND)
-	gen_insn (XSTR (desc, 0), insn_code_number);
+	gen_insn (desc, insn_code_number);
     }
 
-  puts ("CODE_FOR_nothing\n\
+  puts ("  CODE_FOR_nothing\n\
 };\n\
 \n\
 #endif /* GCC_INSN_CODES_H */");