[PATCH] Fix PR69537

[Richard Biener]

I am fixing the missed optimization / bogus warning with relaxing
the guard around "old" fold_{widened,sing_changing}_comparison
which is now in match.pd.

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

I'm curious if any issues with casts-to-BOOLEAN_TYPE show up
in our testsuite (and wonder how we didn't bother to then test
also for casts-from-BOOLEAN_TYPE).

Richard.

2016-01-28  Richard Biener  <rguenther@suse.de>

	PR middle-end/69537
	* match.pd: Allow all integral types when simplifying a
	widening or sign-changing conversion.

	* gcc.dg/uninit-21.c: New testcase.

Index: gcc/match.pd
===================================================================
--- gcc/match.pd	(revision 232925)
+++ gcc/match.pd	(working copy)
@@ -2121,7 +2121,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 (for cmp (simple_comparison)
  (simplify
   (cmp (convert@0 @00) (convert?@1 @10))
-  (if (TREE_CODE (TREE_TYPE (@0)) == INTEGER_TYPE
+  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
        /* Disable this optimization if we're casting a function pointer
 	  type on targets that require function pointer canonicalization.  */
        && !(targetm.have_canonicalize_funcptr_for_compare ()
Index: gcc/testsuite/gcc.dg/uninit-21.c
===================================================================
--- gcc/testsuite/gcc.dg/uninit-21.c	(revision 0)
+++ gcc/testsuite/gcc.dg/uninit-21.c	(working copy)
@@ -0,0 +1,33 @@
+/* PR69537, spurious warning because of a missed optimization. */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wuninitialized" } */
+
+enum clnt_stat {
+ RPC_SUCCESS=0,
+ RPC_CANTENCODEARGS=1,
+};
+ 
+int do_ypcall_tr ();
+ 
+static int
+yp_master (char **outname)
+{
+  // Replacing enum clnt_stat with int avoids the warning.
+  enum clnt_stat result;
+  result = do_ypcall_tr ();
+  if (result != 0)
+    return result;
+  *outname = __builtin_strdup ("foo");
+  return 0;
+}
+ 
+int
+yp_update (void)
+{
+  char *master;
+  int r;
+  if ((r = yp_master (&master)) != 0)
+    return r;
+  __builtin_free (master); /* { dg-bogus "uninitialized" } */
+  return 0;
+}