re PR c/66066 (r222889 causes bogus error: initializer element is not constant)

	PR c/66066
	PR c/66127
	* c-common.c (c_fully_fold): Pass false down to c_fully_fold_internal.
	(c_fully_fold_internal): Fold C_MAYBE_CONST_EXPRs with
	C_MAYBE_CONST_EXPR_INT_OPERANDS set.  Add FOR_INT_CONST argument and
	use it.  If FOR_INT_CONST, require that all evaluated operands be
	INTEGER_CSTs.

	* c-typeck.c (digest_init): Call pedwarn_init with OPT_Wpedantic
	rather than with 0.

	* gcc.dg/pr14649-1.c: Add -Wpedantic.
	* gcc.dg/pr19984.c: Likewise.
	* gcc.dg/pr66066-1.c: New test.
	* gcc.dg/pr66066-2.c: New test.
	* gcc.dg/pr66066-3.c: New test.

From-SVN: r223193

gcc/c-family/ChangeLog

+2015-05-14  Marek Polacek  <polacek@redhat.com>
+
+	PR c/66066
+	PR c/66127
+	* c-common.c (c_fully_fold): Pass false down to c_fully_fold_internal.
+	(c_fully_fold_internal): Fold C_MAYBE_CONST_EXPRs with
+	C_MAYBE_CONST_EXPR_INT_OPERANDS set.  Add FOR_INT_CONST argument and
+	use it.  If FOR_INT_CONST, require that all evaluated operands be
+	INTEGER_CSTs.
+
 2015-05-12  David Malcolm  <dmalcolm@redhat.com>
 
 	* c-common.h (warn_for_misleading_indentation): New prototype.

gcc/c-family/c-common.c

@@ -315,7 +315,7 @@ const struct fname_var_t fname_vars[] =
 /* Global visibility options.  */
 struct visibility_flags visibility_options;
 
-static tree c_fully_fold_internal (tree expr, bool, bool *, bool *);
+static tree c_fully_fold_internal (tree expr, bool, bool *, bool *, bool);
 static tree check_case_value (location_t, tree);
 static bool check_case_bounds (location_t, tree, tree, tree *, tree *);
 
@@ -1148,7 +1148,7 @@ c_fully_fold (tree expr, bool in_init, bool *maybe_const)
       expr = TREE_OPERAND (expr, 0);
     }
   ret = c_fully_fold_internal (expr, in_init, maybe_const,
-			       &maybe_const_itself);
+			       &maybe_const_itself, false);
   if (eptype)
     ret = fold_convert_loc (loc, eptype, ret);
   *maybe_const &= maybe_const_itself;
@@ -1161,11 +1161,13 @@ c_fully_fold (tree expr, bool in_init, bool *maybe_const)
    arithmetic overflow (for C90, *MAYBE_CONST_OPERANDS is carried from
    both evaluated and unevaluated subexpressions while
    *MAYBE_CONST_ITSELF is carried from only evaluated
-   subexpressions).  */
+   subexpressions).  FOR_INT_CONST indicates if EXPR is an expression
+   with integer constant operands, and if any of the operands doesn't
+   get folded to an integer constant, don't fold the expression itself.  */
 
 static tree
 c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
-		       bool *maybe_const_itself)
+		       bool *maybe_const_itself, bool for_int_const)
 {
   tree ret = expr;
   enum tree_code code = TREE_CODE (expr);
@@ -1209,7 +1211,11 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       if (C_MAYBE_CONST_EXPR_NON_CONST (expr))
 	*maybe_const_operands = false;
       if (C_MAYBE_CONST_EXPR_INT_OPERANDS (expr))
-	*maybe_const_itself = false;
+	{
+	  *maybe_const_itself = false;
+	  inner = c_fully_fold_internal (inner, in_init, maybe_const_operands,
+					 maybe_const_itself, true);
+	}
       if (pre && !in_init)
 	ret = build2 (COMPOUND_EXPR, TREE_TYPE (expr), pre, inner);
       else
@@ -1259,7 +1265,7 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       op1 = TREE_OPERAND (expr, 1);
       op2 = TREE_OPERAND (expr, 2);
       op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
-				   maybe_const_itself);
+				   maybe_const_itself, for_int_const);
       STRIP_TYPE_NOPS (op0);
       if (op0 != orig_op0)
 	ret = build3 (COMPONENT_REF, TREE_TYPE (expr), op0, op1, op2);
@@ -1276,10 +1282,10 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       op2 = TREE_OPERAND (expr, 2);
       op3 = TREE_OPERAND (expr, 3);
       op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
-				   maybe_const_itself);
+				   maybe_const_itself, for_int_const);
       STRIP_TYPE_NOPS (op0);
       op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
-				   maybe_const_itself);
+				   maybe_const_itself, for_int_const);
       STRIP_TYPE_NOPS (op1);
       op1 = decl_constant_value_for_optimization (op1);
       if (op0 != orig_op0 || op1 != orig_op1)
@@ -1336,7 +1342,7 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       orig_op0 = op0 = TREE_OPERAND (expr, 0);
       orig_op1 = op1 = TREE_OPERAND (expr, 1);
       op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
-				   maybe_const_itself);
+				   maybe_const_itself, for_int_const);
       STRIP_TYPE_NOPS (op0);
       if (code != MODIFY_EXPR
 	  && code != PREDECREMENT_EXPR
@@ -1348,9 +1354,14 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
 	 expression for the sake of conversion warnings.  */
       if (code != MODIFY_EXPR)
 	op1 = c_fully_fold_internal (op1, in_init, maybe_const_operands,
-				     maybe_const_itself);
+				     maybe_const_itself, for_int_const);
       STRIP_TYPE_NOPS (op1);
       op1 = decl_constant_value_for_optimization (op1);
+
+      if (for_int_const && (TREE_CODE (op0) != INTEGER_CST
+			    || TREE_CODE (op1) != INTEGER_CST))
+	goto out;
+
       if (op0 != orig_op0 || op1 != orig_op1 || in_init)
 	ret = in_init
 	  ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
@@ -1420,10 +1431,14 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       /* Unary operations.  */
       orig_op0 = op0 = TREE_OPERAND (expr, 0);
       op0 = c_fully_fold_internal (op0, in_init, maybe_const_operands,
-				   maybe_const_itself);
+				   maybe_const_itself, for_int_const);
       STRIP_TYPE_NOPS (op0);
       if (code != ADDR_EXPR && code != REALPART_EXPR && code != IMAGPART_EXPR)
 	op0 = decl_constant_value_for_optimization (op0);
+
+      if (for_int_const && TREE_CODE (op0) != INTEGER_CST)
+	goto out;
+
       /* ??? Cope with user tricks that amount to offsetof.  The middle-end is
 	 not prepared to deal with them if they occur in initializers.  */
       if (op0 != orig_op0
@@ -1468,17 +1483,25 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
 	 arguments.  */
       orig_op0 = op0 = TREE_OPERAND (expr, 0);
       orig_op1 = op1 = TREE_OPERAND (expr, 1);
-      op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self);
+      op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
+				   for_int_const);
       STRIP_TYPE_NOPS (op0);
 
       unused_p = (op0 == (code == TRUTH_ANDIF_EXPR
 			  ? truthvalue_false_node
 			  : truthvalue_true_node));
       c_disable_warnings (unused_p);
-      op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self);
+      op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
+				   for_int_const);
       STRIP_TYPE_NOPS (op1);
       c_enable_warnings (unused_p);
 
+      if (for_int_const
+	  && (TREE_CODE (op0) != INTEGER_CST
+	      /* Require OP1 be an INTEGER_CST only if it's evaluated.  */
+	      || (!unused_p && TREE_CODE (op1) != INTEGER_CST)))
+	goto out;
+
       if (op0 != orig_op0 || op1 != orig_op1 || in_init)
 	ret = in_init
 	  ? fold_build2_initializer_loc (loc, code, TREE_TYPE (expr), op0, op1)
@@ -1506,19 +1529,30 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
       orig_op0 = op0 = TREE_OPERAND (expr, 0);
       orig_op1 = op1 = TREE_OPERAND (expr, 1);
       orig_op2 = op2 = TREE_OPERAND (expr, 2);
-      op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self);
+      op0 = c_fully_fold_internal (op0, in_init, &op0_const, &op0_const_self,
+				   for_int_const);
 
       STRIP_TYPE_NOPS (op0);
       c_disable_warnings (op0 == truthvalue_false_node);
-      op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self);
+      op1 = c_fully_fold_internal (op1, in_init, &op1_const, &op1_const_self,
+				   for_int_const);
       STRIP_TYPE_NOPS (op1);
       c_enable_warnings (op0 == truthvalue_false_node);
 
       c_disable_warnings (op0 == truthvalue_true_node);
-      op2 = c_fully_fold_internal (op2, in_init, &op2_const, &op2_const_self);
+      op2 = c_fully_fold_internal (op2, in_init, &op2_const, &op2_const_self,
+				   for_int_const);
       STRIP_TYPE_NOPS (op2);
       c_enable_warnings (op0 == truthvalue_true_node);
 
+      if (for_int_const
+	  && (TREE_CODE (op0) != INTEGER_CST
+	      /* Only the evaluated operand must be an INTEGER_CST.  */
+	      || (op0 == truthvalue_true_node
+		  ? TREE_CODE (op1) != INTEGER_CST
+		  : TREE_CODE (op2) != INTEGER_CST)))
+	goto out;
+
       if (op0 != orig_op0 || op1 != orig_op1 || op2 != orig_op2)
 	ret = fold_build3_loc (loc, code, TREE_TYPE (expr), op0, op1, op2);
       else

gcc/c/ChangeLog

+2015-05-14  Marek Polacek  <polacek@redhat.com>
+
+	PR c/66066
+	PR c/66127
+	* c-typeck.c (digest_init): Call pedwarn_init with OPT_Wpedantic
+	rather than with 0.
+
 2015-05-12  David Malcolm  <dmalcolm@redhat.com>
 
 	* c-parser.c (c_parser_if_body): Add param "if_loc", use it

gcc/c/c-typeck.c

@@ -6864,7 +6864,7 @@ digest_init (location_t init_loc, tree type, tree init, tree origtype,
 	  inside_init = error_mark_node;
 	}
       else if (require_constant && !maybe_const)
-	pedwarn_init (init_loc, 0,
+	pedwarn_init (init_loc, OPT_Wpedantic,
 		      "initializer element is not a constant expression");
 
       /* Added to enable additional -Wsuggest-attribute=format warnings.  */

gcc/testsuite/ChangeLog

+2015-05-14  Marek Polacek  <polacek@redhat.com>
+
+	PR c/66066
+	PR c/66127
+	* gcc.dg/pr14649-1.c: Add -Wpedantic.
+	* gcc.dg/pr19984.c: Likewise.
+	* gcc.dg/pr66066-1.c: New test.
+	* gcc.dg/pr66066-2.c: New test.
+	* gcc.dg/pr66066-3.c: New test.
+
 2015-05-13  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* gcc.target/aarch64/pow-sqrt-synth-1.c: New test.

gcc/testsuite/gcc.dg/pr14649-1.c

 /* PR c/14649 */
 /* { dg-do compile } */
-/* { dg-options "-O2" } */
+/* { dg-options "-O2 -Wpedantic" } */
 
 double atan(double);
 

gcc/testsuite/gcc.dg/pr19984.c

 /* PR c/19984 */
 /* { dg-do compile } */
-/* { dg-options "-O2 -std=c99" } */
+/* { dg-options "-O2 -std=c99 -Wpedantic" } */
 
 
 double nan (const char *);

gcc/testsuite/gcc.dg/pr66066-1.c

+/* PR c/66066 */
+/* { dg-do compile } */
+/* { dg-options "-Wno-div-by-zero" } */
+
+/* Accept these unless -pedantic-errors/-Werror.  */
+int a1 = -1 << 0;
+int a2 = -1 << 0 | 0;
+int a3 = -1 << 0 & 1;
+int a4 = -1 << 2 ^ 1;
+int a5 = 4 & -1 << 2;
+int a6 = (-1 << 2) ^ (1 >> 1);
+int a7 = 0 || (-1 << 1);
+int a8 = 0 ? 2 : (-1 << 1);
+int a9 = 1 && -1 << 0;
+int a10 = !(-1 << 0);
+
+/* Don't accept these.  */
+int b1 = 1 / 0;		/* { dg-error "initializer element is not constant" } */
+int b2 = 1 / (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b3 = 0 ? 2 : 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b4 = 0 || 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b5 = 0 * (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b6 = 1 * (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b7 = (1 / 0) * 0;	/* { dg-error "initializer element is not constant" } */
+int b8 = (1 / 0) * 1;	/* { dg-error "initializer element is not constant" } */
+int b9 = 1 && 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b10 = !(1 / 0);	/* { dg-error "initializer element is not constant" } */
+int c1 = 1 % 0;		/* { dg-error "initializer element is not constant" } */
+int c2 = 1 / (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c3 = 0 ? 2 : 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c4 = 0 || 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c5 = 0 * (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c6 = 1 * (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c7 = (1 % 0) * 0;	/* { dg-error "initializer element is not constant" } */
+int c8 = (1 % 0) * 1;	/* { dg-error "initializer element is not constant" } */
+int c9 = 1 && 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c10 = !(1 % 0);	/* { dg-error "initializer element is not constant" } */

gcc/testsuite/gcc.dg/pr66066-2.c

+/* PR c/66066 */
+/* { dg-do compile } */
+/* { dg-options "-Wno-div-by-zero -Wpedantic" } */
+
+/* Accept these unless -pedantic-errors/-Werror.  */
+int a1 = -1 << 0;		/* { dg-warning "initializer element is not a constant expression" } */
+int a2 = -1 << 0 | 0;		/* { dg-warning "initializer element is not a constant expression" } */
+int a3 = -1 << 0 & 1;		/* { dg-warning "initializer element is not a constant expression" } */
+int a4 = -1 << 2 ^ 1;		/* { dg-warning "initializer element is not a constant expression" } */
+int a5 = 4 & -1 << 2;		/* { dg-warning "initializer element is not a constant expression" } */
+int a6 = (-1 << 2) ^ (1 >> 1);	/* { dg-warning "initializer element is not a constant expression" } */
+int a7 = 0 || (-1 << 1);	/* { dg-warning "initializer element is not a constant expression" } */
+int a8 = 0 ? 2 : (-1 << 1);	/* { dg-warning "initializer element is not a constant expression" } */
+int a9 = 1 && -1 << 0;		/* { dg-warning "initializer element is not a constant expression" } */
+int a10 = !(-1 << 0);		/* { dg-warning "initializer element is not a constant expression" } */
+
+/* Don't accept these.  */
+int b1 = 1 / 0;		/* { dg-error "initializer element is not constant" } */
+int b2 = 1 / (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b3 = 0 ? 2 : 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b4 = 0 || 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b5 = 0 * (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b6 = 1 * (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b7 = (1 / 0) * 0;	/* { dg-error "initializer element is not constant" } */
+int b8 = (1 / 0) * 1;	/* { dg-error "initializer element is not constant" } */
+int b9 = 1 && 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b10 = !(1 / 0);	/* { dg-error "initializer element is not constant" } */
+int c1 = 1 % 0;		/* { dg-error "initializer element is not constant" } */
+int c2 = 1 / (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c3 = 0 ? 2 : 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c4 = 0 || 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c5 = 0 * (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c6 = 1 * (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c7 = (1 % 0) * 0;	/* { dg-error "initializer element is not constant" } */
+int c8 = (1 % 0) * 1;	/* { dg-error "initializer element is not constant" } */
+int c9 = 1 && 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c10 = !(1 % 0);	/* { dg-error "initializer element is not constant" } */

gcc/testsuite/gcc.dg/pr66066-3.c

+/* PR c/66066 */
+/* { dg-do compile } */
+/* { dg-options "-Wno-div-by-zero -pedantic-errors" } */
+
+/* Accept these unless -pedantic-errors/-Werror.  */
+int a1 = -1 << 0;		/* { dg-error "initializer element is not a constant expression" } */
+int a2 = -1 << 0 | 0;		/* { dg-error "initializer element is not a constant expression" } */
+int a3 = -1 << 0 & 1;		/* { dg-error "initializer element is not a constant expression" } */
+int a4 = -1 << 2 ^ 1;		/* { dg-error "initializer element is not a constant expression" } */
+int a5 = 4 & -1 << 2;		/* { dg-error "initializer element is not a constant expression" } */
+int a6 = (-1 << 2) ^ (1 >> 1);	/* { dg-error "initializer element is not a constant expression" } */
+int a7 = 0 || (-1 << 1);	/* { dg-error "initializer element is not a constant expression" } */
+int a8 = 0 ? 2 : (-1 << 1);	/* { dg-error "initializer element is not a constant expression" } */
+int a9 = 1 && -1 << 0;		/* { dg-error "initializer element is not a constant expression" } */
+int a10 = !(-1 << 0);		/* { dg-error "initializer element is not a constant expression" } */
+
+/* Don't accept these.  */
+int b1 = 1 / 0;		/* { dg-error "initializer element is not constant" } */
+int b2 = 1 / (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b3 = 0 ? 2 : 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b4 = 0 || 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b5 = 0 * (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b6 = 1 * (1 / 0);	/* { dg-error "initializer element is not constant" } */
+int b7 = (1 / 0) * 0;	/* { dg-error "initializer element is not constant" } */
+int b8 = (1 / 0) * 1;	/* { dg-error "initializer element is not constant" } */
+int b9 = 1 && 1 / 0;	/* { dg-error "initializer element is not constant" } */
+int b10 = !(1 / 0);	/* { dg-error "initializer element is not constant" } */
+int c1 = 1 % 0;		/* { dg-error "initializer element is not constant" } */
+int c2 = 1 / (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c3 = 0 ? 2 : 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c4 = 0 || 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c5 = 0 * (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c6 = 1 * (1 % 0);	/* { dg-error "initializer element is not constant" } */
+int c7 = (1 % 0) * 0;	/* { dg-error "initializer element is not constant" } */
+int c8 = (1 % 0) * 1;	/* { dg-error "initializer element is not constant" } */
+int c9 = 1 && 1 % 0;	/* { dg-error "initializer element is not constant" } */
+int c10 = !(1 % 0);	/* { dg-error "initializer element is not constant" } */