Patchwork patch to fix PR57091

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Submitter Vladimir Makarov
Date May 1, 2013, 6:56 p.m.
Message ID <51816541.7050800@redhat.com>
Download mbox | patch
Permalink /patch/240799/
State New
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Comments

Vladimir Makarov - May 1, 2013, 6:56 p.m.
The following patch fixes

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57091

The problem was in choosing alternative with AREG class in an insn and 
AREG lives through the insn (until call insn).  Reload chooses 
alternative with GENERAL_REGS.  The problem was solved by tweaking 
alternative costs in process_alt_operands.  Generally speaking, in such 
case LRA could split AREG but because only one insn needs AREG it 
decides that is not profitable.

Successfully bootstrapped and tested on x86/x86-64.

Committed as rev. 198503.

2013-05-01  Vladimir Makarov  <vmakarov@redhat.com>

         PR target/57091
         * lra-constraints.c (best_small_class_operands_num): Remove.
         (process_alt_operands): Remove small_class_operands_num.  Take
         small classes operands into losers and only if the operand is not
         matched.  Modify debugging output.
         (curr_insn_transform): Remove best_small_class_operands_num.
         Print insn name.

2013-05-01  Vladimir Makarov  <vmakarov@redhat.com>

         PR target/57091
         * gcc.target/i386/pr57091.c: New test.

Patch

Index: lra-constraints.c
===================================================================
--- lra-constraints.c	(revision 198432)
+++ lra-constraints.c	(working copy)
@@ -1048,9 +1048,6 @@  static int goal_alt_number;
 /* Number of necessary reloads and overall cost reflecting the
    previous value and other unpleasantness of the best alternative.  */
 static int best_losers, best_overall;
-/* Number of small register classes used for operands of the best
-   alternative.	 */
-static int best_small_class_operands_num;
 /* Overall number hard registers used for reloads.  For example, on
    some targets we need 2 general registers to reload DFmode and only
    one floating point register.	 */
@@ -1326,7 +1323,7 @@  static bool
 process_alt_operands (int only_alternative)
 {
   bool ok_p = false;
-  int nop, small_class_operands_num, overall, nalt;
+  int nop, overall, nalt;
   int n_alternatives = curr_static_id->n_alternatives;
   int n_operands = curr_static_id->n_operands;
   /* LOSERS counts the operands that don't fit this alternative and
@@ -1405,6 +1402,7 @@  process_alt_operands (int only_alternati
       if (only_alternative >= 0 && nalt != only_alternative)
 	continue;
 
+            
       overall = losers = reject = reload_nregs = reload_sum = 0;
       for (nop = 0; nop < n_operands; nop++)
 	reject += (curr_static_id
@@ -2006,6 +2004,9 @@  process_alt_operands (int only_alternati
 		  if (! no_regs_p)
 		    reload_nregs
 		      += ira_reg_class_max_nregs[this_alternative][mode];
+
+		  if (SMALL_REGISTER_CLASS_P (this_alternative))
+		    reject += LRA_LOSER_COST_FACTOR / 2;
 		}
 
 	      /* We are trying to spill pseudo into memory.  It is
@@ -2033,6 +2034,7 @@  process_alt_operands (int only_alternati
 		 reloads.  */
 	      if (!REG_P (op) || curr_static_id->operand[nop].type != OP_IN)
 		reject++;
+
 	    }
 
 	  if (early_clobber_p)
@@ -2178,15 +2180,9 @@  process_alt_operands (int only_alternati
 	      overall += LRA_LOSER_COST_FACTOR - 1;
 	    }
 	}
-      small_class_operands_num = 0;
-      for (nop = 0; nop < n_operands; nop++)
-	small_class_operands_num
-	  += SMALL_REGISTER_CLASS_P (curr_alt[nop]) ? 1 : 0;
-
       if (lra_dump_file != NULL)
-	fprintf (lra_dump_file, "          alt=%d,overall=%d,losers=%d,"
-		 "small_class_ops=%d,rld_nregs=%d\n",
-		 nalt, overall, losers, small_class_operands_num, reload_nregs);
+	fprintf (lra_dump_file, "          alt=%d,overall=%d,losers=%d,rld_nregs=%d\n",
+		 nalt, overall, losers, reload_nregs);
 
       /* If this alternative can be made to work by reloading, and it
 	 needs less reloading than the others checked so far, record
@@ -2198,17 +2194,10 @@  process_alt_operands (int only_alternati
 		  || (best_overall == overall
 		      /* If the cost of the reloads is the same,
 			 prefer alternative which requires minimal
-			 number of small register classes for the
-			 operands.  This improves chances of reloads
-			 for insn requiring small register
-			 classes.  */
-		      && (small_class_operands_num
-			  < best_small_class_operands_num
-			  || (small_class_operands_num
-			      == best_small_class_operands_num
-			      && (reload_nregs < best_reload_nregs
-				  || (reload_nregs == best_reload_nregs
-				      && best_reload_sum < reload_sum))))))))
+			 number of reload regs.  */
+		      && (reload_nregs < best_reload_nregs
+			  || (reload_nregs == best_reload_nregs
+			      && best_reload_sum < reload_sum))))))
 	{
 	  for (nop = 0; nop < n_operands; nop++)
 	    {
@@ -2224,7 +2213,6 @@  process_alt_operands (int only_alternati
 	  goal_alt_swapped = curr_swapped;
 	  best_overall = overall;
 	  best_losers = losers;
-	  best_small_class_operands_num = small_class_operands_num;
 	  best_reload_nregs = reload_nregs;
 	  best_reload_sum = reload_sum;
 	  goal_alt_number = nalt;
@@ -2826,7 +2814,7 @@  curr_insn_transform (void)
      operands together against the register constraints.  */
 
   best_losers = best_overall = INT_MAX;
-  best_small_class_operands_num = best_reload_sum = 0;
+  best_reload_sum = 0;
 
   curr_swapped = false;
   goal_alt_swapped = false;
@@ -3033,7 +3021,10 @@  curr_insn_transform (void)
 	  for (; *p != '\0' && *p != ',' && *p != '#'; p++)
 	    fputc (*p, lra_dump_file);
 	}
-      fprintf (lra_dump_file, "\n");
+      if (INSN_CODE (curr_insn) >= 0
+          && (p = get_insn_name (INSN_CODE (curr_insn))) != NULL)
+        fprintf (lra_dump_file, " {%s}", p);
+       fprintf (lra_dump_file, "\n");
     }
 
   /* Right now, for any pair of operands I and J that are required to
Index: testsuite/gcc.target/i386/pr57091.c
===================================================================
--- testsuite/gcc.target/i386/pr57091.c	(revision 0)
+++ testsuite/gcc.target/i386/pr57091.c	(working copy)
@@ -0,0 +1,8 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O -mcmodel=large"  { target lp64 } } */
+void (*bar)();
+
+void foo (void)
+{
+  bar ();
+}