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Re: [PATCH 4/4] bb-reorder: convert to gcc_stablesort


This converts the use in bb-reorder.  I had to get a little bit creative with
the comparator as profile_count::operator> does not implement a strict weak
order.

	* gcc/bb-reorder.c (edge_order): Convert to C-qsort-style
	tri-state comparator.
	(reorder_basic_blocks_simple): Change std::stable_sort to gcc_stablesort.

diff --git a/gcc/bb-reorder.c b/gcc/bb-reorder.c
index 57edde62c62..7c80609fbf4 100644
--- a/gcc/bb-reorder.c
+++ b/gcc/bb-reorder.c
@@ -91,7 +91,6 @@
 */
 
 #include "config.h"
-#define INCLUDE_ALGORITHM /* stable_sort */
 #include "system.h"
 #include "coretypes.h"
 #include "backend.h"
@@ -2351,13 +2350,17 @@ reorder_basic_blocks_software_trace_cache (void)
   FREE (bbd);
 }
 
-/* Return true if edge E1 is more desirable as a fallthrough edge than
-   edge E2 is.  */
+/* Order edges by execution frequency, higher first.  */
 
-static bool
-edge_order (edge e1, edge e2)
+static int
+edge_order (const void *ve1, const void *ve2)
 {
-  return e1->count () > e2->count ();
+  edge e1 = *(const edge *) ve1;
+  edge e2 = *(const edge *) ve2;
+  profile_count c1 = e1->count ();
+  profile_count c2 = e2->count ();
+  profile_count m = c1.max (c2);
+  return (m == c2) - (m == c1);
 }
 
 /* Reorder basic blocks using the "simple" algorithm.  This tries to
@@ -2410,7 +2413,7 @@ reorder_basic_blocks_simple (void)
      all edges are equally desirable.  */
 
   if (optimize_function_for_speed_p (cfun))
-    std::stable_sort (edges, edges + n, edge_order);
+    gcc_stablesort (edges, n, sizeof *edges, edge_order);
 
   /* Now decide which of those edges to make fallthrough edges.  We set
      BB_VISITED if a block already has a fallthrough successor assigned
-- 
2.13.3


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