* attribs.c (decl_attributes): Avoid emitting a warning if

	ATTR_FLAG_BUILT_IN.
	* doc/rtl.texi (CALL_INSN_FUNCTION_USAGE): Use lowercase for rtx
	codes.  Document meaning of sets inside CALL_INSN_FUNCTION_USAGE.
	* c-family/c-common.c (DEF_ATTR_STRING): Define and undefine as
	necessary.
	* builtin-attrs.def (DEF_ATTR_FOR_STRING): Define.  Use it to
	define a string "1".
	(ATTR_RET1_NOTHROW_NONNULL_LEAF): New attr definition.
	* builtins.def (BUILT_IN_MEMCPY, BUILT_IN_MEMMOVE, BUILT_IN_MEMSET,
	BUILT_IN_STRCPY): Use it for these functions.
	* postreload.c (reload_combine): Deal with SETs inside
	CALL_INSN_FUNCTION_USAGE.
	* caller-save.c (setup_save_areas, save_call_clobbered_regs):
	Look for REG_RETURNED notes and use a cheap restore if possible.
	* ira-int.h (struct ira_allocno): New member cheap_calls_crossed_num.
	(ALLOCNO_CHEAP_CALLS_CROSSED_NUM): New macro.
	* ira-build.c (ira_create_allocno, create_cap_allocno,
	propagate_allocno_info, propagate_some_info_from_allocno,
	copy_info_to_removed_store_destination, ira_flattening): Handle it.
	* ira-lives.c (pseudo_regno_single_word_and_live_p,
	find_call_crossed_cheap_reg): New static functions.
	(process_bb_node_lives): Look for SETs in CALL_INSN_FUNCTION_USAGE,
	and set ALLOCNO_CHEAP_CALLS_CROSSED_NUM if possible.  Also make
	a REG_RETURNED note in that case.
	* ira.c (setup_reg_renumber): Change assert to allow cases where
	allocnos only cross calls for which they are cheap to restore.
	* ira-costs.c (ira_tune_allocno_costs): Compare
	ALLOCNO_CALLS_CROSSED_NUM to ALLOCNO_CHEAP_CALLS_CROSSED_NUM rather
	than 0.
	* reg-notes.def (REG_RETURNED): New note.
	* cse.c (cse_insn): Likewise.
	* sched-deps.c (sched_analyze_insn): Likewise.
	* expr.c (init_block_move_fn): Set a "fn spec" attribute.
	* calls.c (decl_return_flags): New static function.
	(expand_call): Generate a SET in CALL_INSN_FUNCTION_USAGE for
	functions that return one of their arguments.
	* lto/lto-lang.c (handle_fnspec_attribute): New static function.
	(lto_attribute_table): Add "fn spec".
	(DEF_ATTR_STRING): Define and undefine along with the other macros.
	* regcprop.c (struct kill_set_value_data): New.
	(kill_set_value): Interpret data as a pointer to such a struct.
	Do nothing if the caller wants the register to be ignored.
	(copyprop_hardreg_forward_1): Handle SETs in CALL_INSN_FUNCTION_USAGE.

testsuite/
	* gcc.target/i386/retarg.c: New test.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@187459 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 22 insertions, 0 deletions

diff --git a/gcc/lto/lto-lang.c b/gcc/lto/lto-lang.c
index 740193074c6..280d88359de 100644
--- a/gcc/lto/lto-lang.c
+++ b/gcc/lto/lto-lang.c
@@ -53,6 +53,7 @@ static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
 static tree ignore_attribute (tree *, tree, tree, int, bool *);
 
 static tree handle_format_attribute (tree *, tree, tree, int, bool *);
+static tree handle_fnspec_attribute (tree *, tree, tree, int, bool *);
 static tree handle_format_arg_attribute (tree *, tree, tree, int, bool *);
 
 /* Table of machine-independent attributes supported in GIMPLE.  */
@@ -83,6 +84,8 @@ const struct attribute_spec lto_attribute_table[] =
 			      handle_sentinel_attribute, false },
   { "type generic",           0, 0, false, true, true,
 			      handle_type_generic_attribute, false },
+  { "fn spec",	 	      1, 1, false, true, true,
+			      handle_fnspec_attribute, false },
   { "transaction_pure",	      0, 0, false, true, true,
 			      handle_transaction_pure_attribute, false },
   /* For internal use only.  The leading '*' both prevents its usage in
@@ -110,11 +113,13 @@ enum built_in_attribute
 {
 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
+#define DEF_ATTR_STRING(ENUM, VALUE) ENUM,
 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
 #include "builtin-attrs.def"
 #undef DEF_ATTR_NULL_TREE
 #undef DEF_ATTR_INT
+#undef DEF_ATTR_STRING
 #undef DEF_ATTR_IDENT
 #undef DEF_ATTR_TREE_LIST
   ATTR_LAST
@@ -483,6 +488,20 @@ handle_format_arg_attribute (tree * ARG_UNUSED (node), tree ARG_UNUSED (name),
 }
 
 
+/* Handle a "fn spec" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+handle_fnspec_attribute (tree *node ATTRIBUTE_UNUSED, tree ARG_UNUSED (name),
+			 tree args, int ARG_UNUSED (flags),
+			 bool *no_add_attrs ATTRIBUTE_UNUSED)
+{
+  gcc_assert (args
+	      && TREE_CODE (TREE_VALUE (args)) == STRING_CST
+	      && !TREE_CHAIN (args));
+  return NULL_TREE;
+}
+
 /* Cribbed from c-common.c.  */
 
 static void
@@ -568,6 +587,8 @@ lto_init_attributes (void)
   built_in_attributes[(int) ENUM] = NULL_TREE;
 #define DEF_ATTR_INT(ENUM, VALUE)				\
   built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
+#define DEF_ATTR_STRING(ENUM, VALUE)				\
+  built_in_attributes[(int) ENUM] = build_string (strlen (VALUE), VALUE);
 #define DEF_ATTR_IDENT(ENUM, STRING)				\
   built_in_attributes[(int) ENUM] = get_identifier (STRING);
 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN)	\
@@ -578,6 +599,7 @@ lto_init_attributes (void)
 #include "builtin-attrs.def"
 #undef DEF_ATTR_NULL_TREE
 #undef DEF_ATTR_INT
+#undef DEF_ATTR_STRING
 #undef DEF_ATTR_IDENT
 #undef DEF_ATTR_TREE_LIST
 }