introduce ir_bk_may_alias

This can be used to effectively test aliasing in libfirm.

include/libfirm/firm_types.h

@@ -276,23 +276,28 @@ typedef struct ir_asm_constraint {
  * @ingroup Builtin
  */
 typedef enum ir_builtin_kind {
-	ir_bk_trap,                   /**< GCC __builtin_trap(): insert trap */
-	ir_bk_debugbreak,             /**< MS __debugbreak(): insert debug break */
-	ir_bk_return_address,         /**< GCC __builtin_return_address() */
-	ir_bk_frame_address,          /**< GCC __builtin_frame_address() */
-	ir_bk_prefetch,               /**< GCC __builtin_prefetch() */
-	ir_bk_ffs,                    /**< GCC __builtin_ffs(): find first (least) significant 1 bit */
-	ir_bk_clz,                    /**< GCC __builtin_clz(): count leading zero */
-	ir_bk_ctz,                    /**< GCC __builtin_ctz(): count trailing zero */
-	ir_bk_popcount,               /**< GCC __builtin_popcount(): population count */
-	ir_bk_parity,                 /**< GCC __builtin_parity(): parity */
-	ir_bk_bswap,                  /**< byte swap */
-	ir_bk_inport,                 /**< in port */
-	ir_bk_outport,                /**< out port */
-	ir_bk_inner_trampoline,       /**< address of a trampoline for GCC inner functions */
-	ir_bk_saturating_increment,   /**< saturating increment */
-	ir_bk_compare_swap,           /**< compare exchange (aka. compare and swap) */
-	ir_bk_last = ir_bk_compare_swap,
+	ir_bk_trap,                 /**< GCC __builtin_trap(): insert trap */
+	ir_bk_debugbreak,           /**< MS __debugbreak(): insert debug break */
+	ir_bk_return_address,       /**< GCC __builtin_return_address() */
+	ir_bk_frame_address,        /**< GCC __builtin_frame_address() */
+	ir_bk_prefetch,             /**< GCC __builtin_prefetch() */
+	ir_bk_ffs,                  /**< GCC __builtin_ffs(): find first (least)
+	                                 significant 1 bit */
+	ir_bk_clz,                  /**< GCC __builtin_clz(): count leading zero */
+	ir_bk_ctz,                  /**< GCC __builtin_ctz(): count trailing zero */
+	ir_bk_popcount,             /**< GCC __builtin_popcount(): population
+	                                 count */
+	ir_bk_parity,               /**< GCC __builtin_parity(): parity */
+	ir_bk_bswap,                /**< byte swap */
+	ir_bk_inport,               /**< in port */
+	ir_bk_outport,              /**< out port */
+	ir_bk_inner_trampoline,     /**< address of a trampoline for GCC inner
+	                                 functions */
+	ir_bk_saturating_increment, /**< saturating increment */
+	ir_bk_compare_swap,         /**< compare exchange (aka. compare and swap) */
+	ir_bk_may_alias,            /**< replaced by 0 if args cannot alias,
+	                                 1 otherwise */
+	ir_bk_last = ir_bk_may_alias,
 } ir_builtin_kind;
 
 /**

ir/be/arm/arm_transform.c

@@ -1175,6 +1175,7 @@ static ir_node *gen_Builtin(ir_node *node)
 	case ir_bk_inner_trampoline:
 	case ir_bk_saturating_increment:
 	case ir_bk_compare_swap:
+	case ir_bk_may_alias:
 		break;
 	}
 	panic("Builtin %s not implemented", get_builtin_kind_name(kind));
@@ -1210,6 +1211,7 @@ static ir_node *gen_Proj_Builtin(ir_node *proj)
 	case ir_bk_inner_trampoline:
 	case ir_bk_saturating_increment:
 	case ir_bk_compare_swap:
+	case ir_bk_may_alias:
 		break;
 	}
 	panic("Builtin %s not implemented", get_builtin_kind_name(kind));

ir/be/ia32/ia32_transform.c

@@ -5124,6 +5124,8 @@ static ir_node *gen_Builtin(ir_node *node)
 		return gen_saturating_increment(node);
 	case ir_bk_compare_swap:
 		return gen_compare_swap(node);
+	case ir_bk_may_alias:
+		break;
 	}
 	panic("Builtin %s not implemented", get_builtin_kind_name(kind));
 }
@@ -5177,6 +5179,8 @@ static ir_node *gen_Proj_Builtin(ir_node *proj)
 			assert(get_Proj_proj(proj) == pn_Builtin_max+1);
 			return new_r_Proj(new_node, ia32_mode_gp, pn_ia32_CmpXChgMem_res);
 		}
+	case ir_bk_may_alias:
+		break;
 	}
 	panic("Builtin %s not implemented", get_builtin_kind_name(kind));
 }

ir/be/sparc/sparc_transform.c

@@ -2426,6 +2426,8 @@ static ir_node *gen_Builtin(ir_node *node)
 		return gen_compare_swap(node);
 	case ir_bk_saturating_increment:
 		return gen_saturating_increment(node);
+	case ir_bk_may_alias:
+		break;
 	}
 	panic("Builtin %s not implemented", get_builtin_kind_name(kind));
 }
@@ -2467,6 +2469,8 @@ static ir_node *gen_Proj_Builtin(ir_node *proj)
 			assert(pn == pn_Builtin_max+1);
 			return new_r_Proj(new_pred, mode_gp, pn_sparc_Cas_res);
 		}
+	case ir_bk_may_alias:
+		break;
 	}
 	panic("Builtin %s not implemented", get_builtin_kind_name(kind));
 }

ir/ir/irnode.c

@@ -678,6 +678,7 @@ const char *get_builtin_kind_name(ir_builtin_kind kind)
 		X(ir_bk_inner_trampoline);
 		X(ir_bk_saturating_increment);
 		X(ir_bk_compare_swap);
+		X(ir_bk_may_alias);
 	}
 	return "<unknown>";
 #undef X

ir/lower/lower_builtins.c

@@ -42,6 +42,7 @@ static const char *get_builtin_name(ir_builtin_kind kind)
 	case ir_bk_inner_trampoline:
 	case ir_bk_saturating_increment:
 	case ir_bk_compare_swap:
+	case ir_bk_may_alias:
 		break;
 	}
 	abort();
@@ -103,6 +104,33 @@ static void replace_with_call(ir_node *node)
 	turn_into_tuple(node, ARRAY_SIZE(in), in);
 }
 
+static void replace_may_alias(ir_node *node)
+{
+	ir_node *in0   = get_Builtin_param(node, 0);
+	ir_node *in1   = get_Builtin_param(node, 1);
+	ir_type *type  = get_Builtin_type(node);
+	ir_type *type0 = get_pointer_points_to_type(get_method_param_type(type, 0));
+	ir_type *type1 = get_pointer_points_to_type(get_method_param_type(type, 1));
+	if (is_unknown_type(type0))
+		type0 = get_type_for_mode(mode_P);
+	if (is_unknown_type(type1))
+		type1 = get_type_for_mode(mode_P);
+	ir_type *rtype = get_method_res_type(type, 0);
+	ir_mode *rmode = get_type_mode(rtype);
+
+	ir_alias_relation alias = get_alias_relation(in0, type0, in1, type1);
+
+	ir_graph  *irg    = get_irn_irg(node);
+	ir_tarval *resval = alias == ir_no_alias
+	                  ? get_mode_null(rmode) : get_mode_one(rmode);
+	ir_node   *result = new_r_Const(irg, resval);
+	ir_node *const in[] = {
+		[pn_Builtin_M]     = get_Builtin_mem(node),
+		[pn_Builtin_max+1] = result,
+	};
+	turn_into_tuple(node, ARRAY_SIZE(in), in);
+}
+
 static void lower_builtin(ir_node *node, void *env)
 {
 	ir_builtin_kind kind;
@@ -133,6 +161,10 @@ static void lower_builtin(ir_node *node, void *env)
 		replace_with_call(node);
 		return;
 
+	case ir_bk_may_alias:
+		replace_may_alias(node);
+		return;
+
 	case ir_bk_trap:
 	case ir_bk_debugbreak:
 	case ir_bk_return_address:

ir/lower/lower_dw.c

@@ -2509,6 +2509,7 @@ static void lower_Builtin(ir_node *builtin, ir_mode *mode)
 	case ir_bk_inner_trampoline:
 	case ir_bk_saturating_increment:
 	case ir_bk_compare_swap:
+	case ir_bk_may_alias:
 		/* Nothing to do/impossible to lower in a generic way */
 		return;
 	case ir_bk_bswap: