re PR tree-optimization/28839 (ICE in tree-vectorizer.c with -O2 -ftree-vectorize -funswitch-loops)

	PR tree-optimization/28839
	* tree-into-ssa.c (prune_unused_phi_nodes): Take into account kills in
	blocks in that phi arguments appear.

	* gcc.dg/pr28839.c: New test.

From-SVN: r116605

gcc/ChangeLog

+2006-08-31  Zdenek Dvorak <dvorakz@suse.cz>
+
+	PR tree-optimization/28839
+	* tree-into-ssa.c (prune_unused_phi_nodes): Take into account kills in
+	blocks in that phi arguments appear.
+
 2006-08-31  Roger Sayle  <roger@eyesopen.com>
 
 	PR other/22313

gcc/testsuite/ChangeLog

+2006-08-31  Zdenek Dvorak <dvorakz@suse.cz>
+
+	PR tree-optimization/28839
+	* gcc.dg/pr28839.c: New test.
+
 2006-08-31  Andreas Krebbel  <krebbel1@de.ibm.com>
 
 	PR target/24367

gcc/testsuite/gcc.dg/pr28839.c

+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 -msse2 -ftree-vectorize -funswitch-loops" } */
+
+static int ready[10];
+void abort (void);
+void test_once (int t,int t1)
+{
+  int i, repeat;
+  for (i = 0; i < 10; i++)
+    {
+      ready[i] = 0;
+      if (t1)
+	if (b())
+	  abort ();
+    }
+  if (t)
+    abort ();
+}

gcc/tree-into-ssa.c

@@ -977,6 +977,13 @@ prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses)
 	  if (bitmap_bit_p (uses, u))
 	    continue;
 
+	  /* In case there is a kill directly in the use block, do not record
+	     the use (this is also necessary for correctness, as we assume that
+	     uses dominated by a def directly in their block have been filtered
+	     out before).  */
+	  if (bitmap_bit_p (kills, u))
+	    continue;
+
 	  bitmap_set_bit (uses, u);
 	  VEC_safe_push (int, heap, worklist, u);
 	}