* call.c (tourney, build_field_call, equal_functions, joust)

[pf3gnuchains/gcc-fork.git] / gcc / cfganal.c

diff --git a/gcc/cfganal.c b/gcc/cfganal.c
index bc8fff2..170ba44 100644 (file)
--- a/gcc/cfganal.c
+++ b/gcc/cfganal.c
@@ -22,6 +22,8 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 /* This file contains various simple utilities to analyze the CFG.  */
 #include "config.h"
 #include "system.h"
+#include "coretypes.h"
+#include "tm.h"
 #include "rtl.h"
 #include "hard-reg-set.h"
 #include "basic-block.h"
@@ -54,7 +56,31 @@ static void flow_dfs_compute_reverse_finish
   PARAMS ((depth_first_search_ds));
 static void remove_fake_successors     PARAMS ((basic_block));
 static bool need_fake_edge_p           PARAMS ((rtx));
+static bool flow_active_insn_p         PARAMS ((rtx));
 \f
+/* Like active_insn_p, except keep the return value clobber around
+   even after reload.  */
+
+static bool
+flow_active_insn_p (insn)
+     rtx insn;
+{
+  if (active_insn_p (insn))
+    return true;
+
+  /* A clobber of the function return value exists for buggy 
+     programs that fail to return a value.  Its effect is to
+     keep the return value from being live across the entire
+     function.  If we allow it to be skipped, we introduce the
+     possibility for register livetime aborts.  */
+  if (GET_CODE (PATTERN (insn)) == CLOBBER
+      && GET_CODE (XEXP (PATTERN (insn), 0)) == REG
+      && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0)))
+    return true;
+
+  return false;
+}
+
 /* Return true if the block has no effect and only forwards control flow to
    its single destination.  */
 
@@ -69,12 +95,12 @@ forwarder_block_p (bb)
     return false;
 
   for (insn = bb->head; insn != bb->end; insn = NEXT_INSN (insn))
-    if (INSN_P (insn) && active_insn_p (insn))
+    if (INSN_P (insn) && flow_active_insn_p (insn))
       return false;
 
   return (!INSN_P (insn)
          || (GET_CODE (insn) == JUMP_INSN && simplejump_p (insn))
-         || !active_insn_p (insn));
+         || !flow_active_insn_p (insn));
 }
 
 /* Return nonzero if we can reach target from src by falling through.  */
@@ -1110,7 +1136,7 @@ int
 dfs_enumerate_from (bb, reverse, predicate, rslt, rslt_max, data)
      basic_block bb;
      int reverse;
-     bool (*predicate) (basic_block, void *);
+     bool (*predicate) PARAMS ((basic_block, void *));
      basic_block *rslt;
      int rslt_max;
      void *data;