re PR tree-optimization/78482 (wrong code at -O3 in both 32-bit and 64-bit modes…

re PR tree-optimization/78482 (wrong code at -O3 in both 32-bit and 64-bit modes on x86_64-linux-gnu)

2016-11-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78482
	* tree-cfgcleanup.c: Include tree-ssa-loop-niter.h.
	(remove_forwarder_block_with_phi): When merging with a loop
	header creates a new latch reset number of iteration information
	of the loop.

	* gcc.dg/torture/pr78482.c: New testcase.

From-SVN: r242754

gcc/ChangeLog

+2016-11-23  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78482
+	* tree-cfgcleanup.c: Include tree-ssa-loop-niter.h.
+	(remove_forwarder_block_with_phi): When merging with a loop
+	header creates a new latch reset number of iteration information
+	of the loop.
+
 2016-11-23  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* config/sparc/sparc.md (*ashrsi3_extend): Rename to...

gcc/testsuite/ChangeLog

+2016-11-23  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78482
+	* gcc.dg/torture/pr78482.c: New testcase.
+
 2016-11-23  Bin Cheng  <bin.cheng@arm.com>
 
 	* gcc.dg/fold-cond_expr-1.c: New test.

gcc/testsuite/gcc.dg/torture/pr78482.c

+/* { dg-do run } */
+
+int printf(const char*, ...);
+short a = 65531;
+int b = 3, f;
+char c, d;
+static void fn1(int p1)
+{
+  short e;
+  b = f;
+  if (f > p1 && p1)
+    L:
+	for (e = 0; 0;)
+	  ;
+  else if (d) b = 0 >= b;
+  for (; e <= 3; e++)
+    {
+      if (b)
+	continue;
+      b = 3;
+      goto L;
+    }
+}
+
+int main()
+{
+  for (; c >= 0; c--)
+    {
+      if (!b)
+	{
+	  printf("%d\n", 2);
+	  continue;
+	}
+      fn1(a);
+    }
+  return 0;
+}

gcc/tree-cfgcleanup.c

@@ -42,6 +42,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-scalar-evolution.h"
 #include "gimple-match.h"
 #include "gimple-fold.h"
+#include "tree-ssa-loop-niter.h"
 
 
 /* The set of blocks in that at least one of the following changes happened:
@@ -885,6 +886,19 @@ remove_forwarder_block_with_phi (basic_block bb)
 	     DEST.  */
 	  e = single_succ_edge (split_edge (e));
 	}
+      else
+	{
+	  /* If we merge the forwarder into a loop header verify if we
+	     are creating another loop latch edge.  If so, reset
+	     number of iteration information of the loop.  */
+	  if (dest->loop_father->header == dest
+	      && dominated_by_p (CDI_DOMINATORS, e->src, dest))
+	    {
+	      dest->loop_father->any_upper_bound = false;
+	      dest->loop_father->any_likely_upper_bound = false;
+	      free_numbers_of_iterations_estimates_loop (dest->loop_father);
+	    }
+	}
 
       s = redirect_edge_and_branch (e, dest);