ipa-devirt.c (ipa_devirt): Drop polymorphic call info in hopeless cases.

	* ipa-devirt.c (ipa_devirt): Drop polymorphic call info in hopeless
	cases.

From-SVN: r219858

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c0e751d9ee77ef484c4bd043327c963f5aba4db8..25c3bc1b2e596c42427c29f82f9bedbad4b2f4a4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2015-01-19  Jan Hubicka  <hubicka@ucw.cz>
+
+       * ipa-devirt.c (ipa_devirt): Drop polymorphic call info in hopeless
+       cases.
+
 2015-01-19  Vladimir Makarov  <vmakarov@redhat.com>
 
        PR rtl-optimization/64671

diff --git a/gcc/ipa-devirt.c b/gcc/ipa-devirt.c
index 70f2bc88bd571d7df9ec41bc5944374da12163cb..aaffa3cbb2f2a24eb4bb71c128b129234b9f4bb0 100644 (file)
--- a/gcc/ipa-devirt.c
+++ b/gcc/ipa-devirt.c
@@ -2815,6 +2815,7 @@ ipa_devirt (void)
   int npolymorphic = 0, nspeculated = 0, nconverted = 0, ncold = 0;
   int nmultiple = 0, noverwritable = 0, ndevirtualized = 0, nnotdefined = 0;
   int nwrong = 0, nok = 0, nexternal = 0, nartificial = 0;
+  int ndropped = 0;
 
   if (!odr_types_ptr)
     return 0;
@@ -2865,6 +2866,28 @@ ipa_devirt (void)
 
            npolymorphic++;
 
+           /* See if the call can be devirtualized by means of ipa-prop's
+              polymorphic call context propagation.  If not, we can just
+              forget about this call being polymorphic and avoid some heavy
+              lifting in remove_unreachable_nodes that will otherwise try to
+              keep all possible targets alive until inlining and in the inliner
+              itself.
+
+              This may need to be revisited once we add further ways to use
+              the may edges, but it is a resonable thing to do right now.  */
+
+           if ((e->indirect_info->param_index == -1
+               || (!opt_for_fn (n->decl, flag_devirtualize_speculatively)
+                   && e->indirect_info->vptr_changed))
+               && !flag_ltrans_devirtualize)
+             {
+               e->indirect_info->polymorphic = false;
+               ndropped++;
+               if (dump_file)
+                 fprintf (dump_file, "Dropping polymorphic call info;"
+                          " it can not be used by ipa-prop\n");
+             }
+
            if (!opt_for_fn (n->decl, flag_devirtualize_speculatively))
              continue;
 
@@ -3094,11 +3117,11 @@ ipa_devirt (void)
             " %i speculatively devirtualized, %i cold\n"
             "%i have multiple targets, %i overwritable,"
             " %i already speculated (%i agree, %i disagree),"
-            " %i external, %i not defined, %i artificial\n",
+            " %i external, %i not defined, %i artificial, %i infos dropped\n",
             npolymorphic, ndevirtualized, nconverted, ncold,
             nmultiple, noverwritable, nspeculated, nok, nwrong,
-            nexternal, nnotdefined, nartificial);
-  return ndevirtualized ? TODO_remove_functions : 0;
+            nexternal, nnotdefined, nartificial, ndropped);
+  return ndevirtualized || ndropped ? TODO_remove_functions : 0;
 }
 
 namespace {