re PR rtl-optimization/46755 (ICE: in calc_dfs_tree, at dominance.c:395 with -O)

gcc/
	PR rtl-optimization/46755
	* ira.c (ira): If some dead edges were removed, find and delete
	any blocks that might have become unreachable.

testsuite/
	PR rtl-optimization/46755
	* gfortran.dg/pr46755.f: New test

From-SVN: r168118

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2010-12-21  Steven Bosscher  <steven@gcc.gnu.org>
+
+	PR rtl-optimization/46755
+	* ira.c (ira): If some dead edges were removed, find and delete
+	any blocks that might have become unreachable.
+
 2010-12-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/47008

gcc/ira.c

@@ -3158,7 +3158,8 @@ ira (FILE *f)
 	{
 	  timevar_push (TV_JUMP);
 	  rebuild_jump_labels (get_insns ());
-	  purge_all_dead_edges ();
+	  if (purge_all_dead_edges ())
+	    delete_unreachable_blocks ();
 	  timevar_pop (TV_JUMP);
 	}
     }

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2010-12-21  Steven Bosscher  <steven@gcc.gnu.org>
+
+	PR rtl-optimization/46755
+	* gfortran.dg/pr46755.f: New test.
+
 2010-12-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/47008

gcc/testsuite/gfortran.dg/pr46755.f

@@ -0,0 +1,23 @@
+C { dg-do compile }
+C { dg-options "-O" }
+      IMPLICIT NONE
+      INTEGER I640,I760,I800
+      INTEGER I,ITER,ITMX,LENCM
+      LOGICAL QDISK,QDW
+      ASSIGN 801 TO I800
+      GOTO I800
+ 801  CONTINUE
+      ASSIGN 761 TO I760
+ 761  CONTINUE
+      DO I=1,LENCM
+      ENDDO
+      DO WHILE(ITER.LT.ITMX)
+         IF(QDW) THEN
+            ASSIGN 641 to I640
+            GOTO I760
+ 641        CONTINUE
+         ENDIF
+      ENDDO
+      RETURN
+      END
+