re PR tree-optimization/55684 (ICE in remove_redundant_iv_tests, at tree-ssa-loop-ivcanon.c:559)

2012-12-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/55684
	* tree-ssa-loop-ivcanon.c (remove_redundant_iv_tests): Handle
	gracefully the case where we cannot compute the number of
	iterations at an exit.

	* gcc.dg/torture/pr55684.c: New testcase.

From-SVN: r194499

gcc/ChangeLog

 2012-12-14  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/55684
+	* tree-ssa-loop-ivcanon.c (remove_redundant_iv_tests): Handle
+	gracefully the case where we cannot compute the number of
+	iterations at an exit.
+
+2012-12-14  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/55687
 	* tree-chrec.h (no_evolution_in_loop_p): Properly use
 	tree_contains_chrecs.

gcc/testsuite/ChangeLog

 2012-12-14  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/55684
+	* gcc.dg/torture/pr55684.c: New testcase.
+
+2012-12-14  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/55687
 	* gcc.dg/torture/pr55687.c: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr55684.c

+/* { dg-do compile } */
+
+typedef struct _IO_FILE FILE;
+unsigned long int strtoul(const char *, char **, int);
+char *fgets(char *, int, FILE *);
+struct ihexrec {
+    unsigned char reclen;
+    unsigned char data[256];
+};
+static void srec_readrec(struct ihexrec * srec, char * rec)
+{
+  int i, j;
+  char buf[8];
+  int offset = 0, len;
+  char * e;
+  for (i=0; j<srec->reclen; j++)
+    {
+      if (offset+2 > len)
+        return;
+      for (i=0; i<2; i++)
+        buf[i] = rec[offset++];
+      srec->data[j] = strtoul(buf, &e, 16);
+    }
+  for (i=0; i<2; i++)
+    buf[i] = rec[offset++];
+}
+void srec2b(FILE *inf)
+{
+  char buffer[256];
+  struct ihexrec srec;
+  while (fgets(buffer,256,inf)!=(void *)0)
+    srec_readrec(&srec, buffer);
+}

gcc/tree-ssa-loop-ivcanon.c

@@ -555,9 +555,8 @@ remove_redundant_iv_tests (struct loop *loop)
 	  /* Only when we know the actual number of iterations, not
 	     just a bound, we can remove the exit.  */
 	  if (!number_of_iterations_exit (loop, exit_edge,
-					  &niter, false, false))
-	    gcc_unreachable ();
-	  if (!integer_onep (niter.assumptions)
+					  &niter, false, false)
+	      || !integer_onep (niter.assumptions)
 	      || !integer_zerop (niter.may_be_zero)
 	      || !niter.niter
 	      || TREE_CODE (niter.niter) != INTEGER_CST