combine: Print insns with the cost dump

In the combine dump file, at the start there is a list of the RTL cost
of every insn.  The only thing listed about the insns is the UID though.
To make it more useful, this patch prints the insn itself as well (in
slim format).


	* combine.c (combine_instructions): Print insns to dump_file, together
	with their costs.

From-SVN: r249802

gcc/ChangeLog

+2017-06-29  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	* combine.c (combine_instructions): Print insns to dump_file, together
+	with their costs.
+
 2017-06-29  Jan Hubicka  <hubicka@ucw.cz>
 
 	* asan.c (asan_emit_stack_protection): Update.

gcc/combine.c

@@ -1213,8 +1213,10 @@ combine_instructions (rtx_insn *f, unsigned int nregs)
 	      INSN_COST (insn) = insn_rtx_cost (PATTERN (insn),
 	      					optimize_this_for_speed_p);
 	    if (dump_file)
-	      fprintf (dump_file, "insn_cost %d: %d\n",
-		       INSN_UID (insn), INSN_COST (insn));
+	      {
+		fprintf (dump_file, "insn_cost %d for ", INSN_COST (insn));
+		dump_insn_slim (dump_file, insn);
+	      }
 	  }
     }