re PR c++/71537 (GCC rejects consetxpr boolean conversions and comparisons on…

re PR c++/71537 (GCC rejects consetxpr boolean conversions and comparisons on the result of pointer arithmetic.)

	PR c++/71537
	* fold-const.c (maybe_nonzero_address): Return 1 for function
	local objects.
	(tree_single_nonzero_warnv_p): Don't handle function local objects
	here.

	* g++.dg/cpp1y/constexpr-71537.C: New test.

From-SVN: r244333

gcc/ChangeLog

 2017-01-11  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/71537
+	* fold-const.c (maybe_nonzero_address): Return 1 for function
+	local objects.
+	(tree_single_nonzero_warnv_p): Don't handle function local objects
+	here.
+
 	PR c++/72813
 	* gcc.c (default_compilers): Don't add -o %g.s for -S -save-temps
 	of c-header.

gcc/fold-const.c

@@ -8171,7 +8171,8 @@ pointer_may_wrap_p (tree base, tree offset, HOST_WIDE_INT bitpos)
 /* Return a positive integer when the symbol DECL is known to have
    a nonzero address, zero when it's known not to (e.g., it's a weak
    symbol), and a negative integer when the symbol is not yet in the
-   symbol table and so whether or not its address is zero is unknown.  */
+   symbol table and so whether or not its address is zero is unknown.
+   For function local objects always return positive integer.  */
 static int
 maybe_nonzero_address (tree decl)
 {
@@ -8179,6 +8180,13 @@ maybe_nonzero_address (tree decl)
     if (struct symtab_node *symbol = symtab_node::get_create (decl))
       return symbol->nonzero_address ();
 
+  /* Function local objects are never NULL.  */
+  if (DECL_P (decl)
+      && (DECL_CONTEXT (decl)
+      && TREE_CODE (DECL_CONTEXT (decl)) == FUNCTION_DECL
+      && auto_var_in_fn_p (decl, DECL_CONTEXT (decl))))
+    return 1;
+
   return -1;
 }
 
@@ -13276,13 +13284,6 @@ tree_single_nonzero_warnv_p (tree t, bool *strict_overflow_p)
 	if (nonzero_addr >= 0)
 	  return nonzero_addr;
 
-	/* Function local objects are never NULL.  */
-	if (DECL_P (base)
-	    && (DECL_CONTEXT (base)
-		&& TREE_CODE (DECL_CONTEXT (base)) == FUNCTION_DECL
-		&& auto_var_in_fn_p (base, DECL_CONTEXT (base))))
-	  return true;
-
 	/* Constants are never weak.  */
 	if (CONSTANT_CLASS_P (base))
 	  return true;

gcc/testsuite/ChangeLog

 2017-01-11  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/71537
+	* g++.dg/cpp1y/constexpr-71537.C: New test.
+
 	* gcc.dg/tree-ssa/flatten-3.c: Add quotation marks around dg-options
 	argument.
 

gcc/testsuite/g++.dg/cpp1y/constexpr-71537.C

+// PR c++/71537
+// { dg-do compile { target c++14 } }
+
+constexpr bool
+foo ()
+{
+  constexpr int n[42] = { 1 };
+  constexpr int o = n ? 1 : 0;
+  constexpr int p = n + 1 ? 1 : 0;
+  constexpr int q = "abc" + 1 ? 1 : 0;
+  return p + p + q == 3;
+}
+
+static_assert (foo (), "");