* builtin-types.def (BT_FN_PTR_CONST_PTR_SIZE_VAR): New.

	* builtins.def (BUILT_IN_ASSUME_ALIGNED): New builtin.
	* tree-ssa-structalias.c (find_func_aliases_for_builtin_call,
	find_func_clobbers): Handle BUILT_IN_ASSUME_ALIGNED.
	* tree-ssa-ccp.c (bit_value_assume_aligned): New function.
	(evaluate_stmt, execute_fold_all_builtins): Handle
	BUILT_IN_ASSUME_ALIGNED.
	* tree-ssa-dce.c (propagate_necessity): Likewise.
	* tree-ssa-alias.c (ref_maybe_used_by_call_p_1,
	call_may_clobber_ref_p_1): Likewise.
	* builtins.c (is_simple_builtin, expand_builtin): Likewise.
	(expand_builtin_assume_aligned): New function.
	* doc/extend.texi (__builtin_assume_aligned): Document.

	* c-common.c (check_builtin_function_arguments): Handle
	BUILT_IN_ASSUME_ALIGNED.

	* gcc.dg/builtin-assume-aligned-1.c: New test.
	* gcc.dg/builtin-assume-aligned-2.c: New test.
	* gcc.target/i386/builtin-assume-aligned-1.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@175541 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 67 insertions, 0 deletions

diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index fd95abbc8e7..78724de286b 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -1476,6 +1476,64 @@ bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2)
   return val;
 }
 
+/* Return the propagation value when applying __builtin_assume_aligned to
+   its arguments.  */
+
+static prop_value_t
+bit_value_assume_aligned (gimple stmt)
+{
+  tree ptr = gimple_call_arg (stmt, 0), align, misalign = NULL_TREE;
+  tree type = TREE_TYPE (ptr);
+  unsigned HOST_WIDE_INT aligni, misaligni = 0;
+  prop_value_t ptrval = get_value_for_expr (ptr, true);
+  prop_value_t alignval;
+  double_int value, mask;
+  prop_value_t val;
+  if (ptrval.lattice_val == UNDEFINED)
+    return ptrval;
+  gcc_assert ((ptrval.lattice_val == CONSTANT
+	       && TREE_CODE (ptrval.value) == INTEGER_CST)
+	      || double_int_minus_one_p (ptrval.mask));
+  align = gimple_call_arg (stmt, 1);
+  if (!host_integerp (align, 1))
+    return ptrval;
+  aligni = tree_low_cst (align, 1);
+  if (aligni <= 1
+      || (aligni & (aligni - 1)) != 0)
+    return ptrval;
+  if (gimple_call_num_args (stmt) > 2)
+    {
+      misalign = gimple_call_arg (stmt, 2);
+      if (!host_integerp (misalign, 1))
+	return ptrval;
+      misaligni = tree_low_cst (misalign, 1);
+      if (misaligni >= aligni)
+	return ptrval;
+    }
+  align = build_int_cst_type (type, -aligni);
+  alignval = get_value_for_expr (align, true);
+  bit_value_binop_1 (BIT_AND_EXPR, type, &value, &mask,
+		     type, value_to_double_int (ptrval), ptrval.mask,
+		     type, value_to_double_int (alignval), alignval.mask);
+  if (!double_int_minus_one_p (mask))
+    {
+      val.lattice_val = CONSTANT;
+      val.mask = mask;
+      gcc_assert ((mask.low & (aligni - 1)) == 0);
+      gcc_assert ((value.low & (aligni - 1)) == 0);
+      value.low |= misaligni;
+      /* ???  Delay building trees here.  */
+      val.value = double_int_to_tree (type, value);
+    }
+  else
+    {
+      val.lattice_val = VARYING;
+      val.value = NULL_TREE;
+      val.mask = double_int_minus_one;
+    }
+  return val;
+}
+
 /* Evaluate statement STMT.
    Valid only for assignments, calls, conditionals, and switches. */
 
@@ -1647,6 +1705,10 @@ evaluate_stmt (gimple stmt)
 	      val = get_value_for_expr (gimple_call_arg (stmt, 0), true);
 	      break;
 
+	    case BUILT_IN_ASSUME_ALIGNED:
+	      val = bit_value_assume_aligned (stmt);
+	      break;
+
 	    default:;
 	    }
 	}
@@ -2186,6 +2248,11 @@ execute_fold_all_builtins (void)
                 result = integer_zero_node;
 		break;
 
+	      case BUILT_IN_ASSUME_ALIGNED:
+		/* Remove __builtin_assume_aligned.  */
+		result = gimple_call_arg (stmt, 0);
+		break;
+
 	      case BUILT_IN_STACK_RESTORE:
 		result = optimize_stack_restore (i);
 		if (result)