Hi,
this patch marks the obvious candidates for cold attribute and enables
cold auto-detection on some common coding patterns.
I have bootstrapped/regtested x86_64-linux and plan to commit it at
weekend once performance testers pick up this weeks changes if there
are no complains.
Honza
* builtin-attrs.def (ATTR_NORETURN_NOTHROW_LEAF_COLD_LIST,
ATTR_CONST_NORETURN_NOTHROW_LEAF_COLD_LIST,
ATTR_TMPURE_NORETURN_NOTHROW_LEAF_COLD_LIST): New.
* builtins.def (abort, trap, unreachable): Declare cold.
* calls.c (flags_from_decl_or_type): Lookup ECF_COLD.
* tree-core.h (ECF_COLD): New.
* tree.c (set_call_expr_flags): Handle ECF_COLD.
(build_common_builtin_nodes): Mark unreachable and abort as cold.
* class.c (build_vtbl_initializer): Mark dvirt_fn as cold.
* decl.c (cxx_init_decl_processing, push_throw_library_fn): Likewise.
(excpet.c): Mark terminate as cold.
* gcc.dg/predict-14.c: Avoid cold function detection.
* gcc.target/i386/umod-3.c: Likewise.
Index: builtin-attrs.def
===================================================================
--- builtin-attrs.def (revision 249057)
+++ builtin-attrs.def (working copy)
@@ -136,6 +136,8 @@ DEF_ATTR_TREE_LIST (ATTR_NORETURN_NOTHRO
ATTR_NULL, ATTR_NOTHROW_LIST)
DEF_ATTR_TREE_LIST (ATTR_NORETURN_NOTHROW_LEAF_LIST, ATTR_NORETURN,\
ATTR_NULL, ATTR_NOTHROW_LEAF_LIST)
+DEF_ATTR_TREE_LIST (ATTR_NORETURN_NOTHROW_LEAF_COLD_LIST, ATTR_COLD,\
+ ATTR_NULL, ATTR_NORETURN_NOTHROW_LEAF_LIST)
DEF_ATTR_TREE_LIST (ATTR_RT_NOTHROW_LEAF_LIST, ATTR_RETURNS_TWICE,\
ATTR_NULL, ATTR_NOTHROW_LEAF_LIST)
DEF_ATTR_TREE_LIST (ATTR_COLD_NOTHROW_LEAF_LIST, ATTR_COLD,\
@@ -144,6 +146,8 @@ DEF_ATTR_TREE_LIST (ATTR_COLD_NORETURN_N
ATTR_NULL, ATTR_NORETURN_NOTHROW_LEAF_LIST)
DEF_ATTR_TREE_LIST (ATTR_CONST_NORETURN_NOTHROW_LEAF_LIST, ATTR_CONST,\
ATTR_NULL, ATTR_NORETURN_NOTHROW_LEAF_LIST)
+DEF_ATTR_TREE_LIST (ATTR_CONST_NORETURN_NOTHROW_LEAF_COLD_LIST, ATTR_COLD,\
+ ATTR_NULL, ATTR_CONST_NORETURN_NOTHROW_LEAF_LIST)
DEF_ATTR_TREE_LIST (ATTR_MALLOC_NOTHROW_LIST, ATTR_MALLOC, \
ATTR_NULL, ATTR_NOTHROW_LIST)
DEF_ATTR_TREE_LIST (ATTR_MALLOC_NOTHROW_LEAF_LIST, ATTR_MALLOC, \
@@ -387,6 +391,9 @@ DEF_ATTR_TREE_LIST (ATTR_TMPURE_NOTHROW_
ATTR_TM_TMPURE, ATTR_NULL, ATTR_NOTHROW_LEAF_LIST)
DEF_ATTR_TREE_LIST (ATTR_TMPURE_NORETURN_NOTHROW_LEAF_LIST,
ATTR_TM_TMPURE, ATTR_NULL, ATTR_NORETURN_NOTHROW_LEAF_LIST)
+DEF_ATTR_TREE_LIST (ATTR_TMPURE_NORETURN_NOTHROW_LEAF_COLD_LIST,
+ ATTR_COLD, ATTR_NULL,
+ ATTR_TMPURE_NORETURN_NOTHROW_LEAF_LIST)
/* Construct a tree for a format_arg attribute. */
#define DEF_FORMAT_ARG_ATTRIBUTE(FA) \
Index: builtins.def
===================================================================
--- builtins.def (revision 249057)
+++ builtins.def (working copy)
@@ -775,7 +775,7 @@ DEF_GCC_BUILTIN (BUILT_IN_UMULL_O
DEF_GCC_BUILTIN (BUILT_IN_UMULLL_OVERFLOW, "umulll_overflow",
BT_FN_BOOL_ULONGLONG_ULONGLONG_ULONGLONGPTR, ATTR_NOTHROW_NONNULL_LEAF_LIST)
/* Category: miscellaneous builtins. */
-DEF_LIB_BUILTIN (BUILT_IN_ABORT, "abort", BT_FN_VOID,
ATTR_TMPURE_NORETURN_NOTHROW_LEAF_LIST)
+DEF_LIB_BUILTIN (BUILT_IN_ABORT, "abort", BT_FN_VOID,
ATTR_TMPURE_NORETURN_NOTHROW_LEAF_COLD_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ABS, "abs", BT_FN_INT_INT,
ATTR_CONST_NOTHROW_LEAF_LIST)
DEF_GCC_BUILTIN (BUILT_IN_AGGREGATE_INCOMING_ADDRESS,
"aggregate_incoming_address", BT_FN_PTR_VAR, ATTR_LEAF_LIST)
DEF_EXT_LIB_BUILTIN (BUILT_IN_ALLOCA, "alloca", BT_FN_PTR_SIZE,
ATTR_ALLOCA_SIZE_1_NOTHROW_LEAF_LIST)
@@ -881,8 +881,8 @@ DEF_GCC_BUILTIN (BUILT_IN_SAVEREG
DEF_GCC_BUILTIN (BUILT_IN_SETJMP, "setjmp", BT_FN_INT_PTR,
ATTR_RT_NOTHROW_LEAF_LIST)
DEF_EXT_LIB_BUILTIN (BUILT_IN_STRFMON, "strfmon",
BT_FN_SSIZE_STRING_SIZE_CONST_STRING_VAR, ATTR_FORMAT_STRFMON_NOTHROW_3_4)
DEF_LIB_BUILTIN (BUILT_IN_STRFTIME, "strftime",
BT_FN_SIZE_STRING_SIZE_CONST_STRING_CONST_TM_PTR,
ATTR_FORMAT_STRFTIME_NOTHROW_3_0)
-DEF_GCC_BUILTIN (BUILT_IN_TRAP, "trap", BT_FN_VOID,
ATTR_NORETURN_NOTHROW_LEAF_LIST)
-DEF_GCC_BUILTIN (BUILT_IN_UNREACHABLE, "unreachable", BT_FN_VOID,
ATTR_CONST_NORETURN_NOTHROW_LEAF_LIST)
+DEF_GCC_BUILTIN (BUILT_IN_TRAP, "trap", BT_FN_VOID,
ATTR_NORETURN_NOTHROW_LEAF_COLD_LIST)
+DEF_GCC_BUILTIN (BUILT_IN_UNREACHABLE, "unreachable", BT_FN_VOID,
ATTR_CONST_NORETURN_NOTHROW_LEAF_COLD_LIST)
DEF_GCC_BUILTIN (BUILT_IN_UNWIND_INIT, "unwind_init", BT_FN_VOID,
ATTR_NULL)
DEF_GCC_BUILTIN (BUILT_IN_UPDATE_SETJMP_BUF, "update_setjmp_buf",
BT_FN_VOID_PTR, ATTR_NULL)
DEF_GCC_BUILTIN (BUILT_IN_VA_COPY, "va_copy",
BT_FN_VOID_VALIST_REF_VALIST_ARG, ATTR_NOTHROW_LEAF_LIST)
Index: calls.c
===================================================================
--- calls.c (revision 249057)
+++ calls.c (working copy)
@@ -821,6 +821,8 @@ flags_from_decl_or_type (const_tree exp)
flags |= ECF_NOVOPS;
if (lookup_attribute ("leaf", DECL_ATTRIBUTES (exp)))
flags |= ECF_LEAF;
+ if (lookup_attribute ("cold", DECL_ATTRIBUTES (exp)))
+ flags |= ECF_COLD;
if (TREE_NOTHROW (exp))
flags |= ECF_NOTHROW;
Index: cp/class.c
===================================================================
--- cp/class.c (revision 249057)
+++ cp/class.c (working copy)
@@ -9727,7 +9727,7 @@ build_vtbl_initializer (tree binfo,
dvirt_fn = push_library_fn
(name,
build_function_type_list (void_type_node, NULL_TREE),
- NULL_TREE, ECF_NORETURN);
+ NULL_TREE, ECF_NORETURN | ECF_COLD);
}
fn = dvirt_fn;
if (!TARGET_VTABLE_USES_DESCRIPTORS)
Index: cp/decl.c
===================================================================
--- cp/decl.c (revision 249057)
+++ cp/decl.c (working copy)
@@ -4269,7 +4269,7 @@ cxx_init_decl_processing (void)
abort_fndecl
= build_library_fn_ptr ("__cxa_pure_virtual", void_ftype,
- ECF_NORETURN | ECF_NOTHROW);
+ ECF_NORETURN | ECF_NOTHROW | ECF_COLD);
/* Perform other language dependent initializations. */
init_class_processing ();
@@ -4550,7 +4550,7 @@ push_void_library_fn (tree name, tree pa
tree
push_throw_library_fn (tree name, tree type)
{
- tree fn = push_library_fn (name, type, NULL_TREE, ECF_NORETURN);
+ tree fn = push_library_fn (name, type, NULL_TREE, ECF_NORETURN | ECF_COLD);
return fn;
}
Index: cp/except.c
===================================================================
--- cp/except.c (revision 249057)
+++ cp/except.c (working copy)
@@ -54,9 +54,10 @@ init_exception_processing (void)
push_namespace (std_identifier);
tmp = build_function_type_list (void_type_node, NULL_TREE);
terminate_fn = build_cp_library_fn_ptr ("terminate", tmp,
- ECF_NOTHROW | ECF_NORETURN);
- TREE_THIS_VOLATILE (terminate_fn) = 1;
- TREE_NOTHROW (terminate_fn) = 1;
+ ECF_NOTHROW | ECF_NORETURN
+ | ECF_COLD);
+ gcc_checking_assert (TREE_THIS_VOLATILE (terminate_fn)
+ && TREE_NOTHROW (terminate_fn));
pop_namespace ();
/* void __cxa_call_unexpected(void *); */
Index: testsuite/gcc.dg/predict-14.c
===================================================================
--- testsuite/gcc.dg/predict-14.c (revision 249057)
+++ testsuite/gcc.dg/predict-14.c (working copy)
@@ -1,16 +1,18 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-profile_estimate" } */
+void test(void) __attribute__ ((noreturn));
+
int main(int argc, char **argv)
{
switch (argc)
{
case 1:
- __builtin_abort();
+ test();
case 4:
- __builtin_abort();
+ test();
default:
- __builtin_abort();
+ test();
}
return 10;
Index: testsuite/gcc.target/i386/umod-3.c
===================================================================
--- testsuite/gcc.target/i386/umod-3.c (revision 249057)
+++ testsuite/gcc.target/i386/umod-3.c (working copy)
@@ -1,7 +1,6 @@
/* { dg-do compile } */
/* { dg-options "-O2 -mtune=atom" } */
-extern void abort (void);
extern void exit (int);
unsigned char cx = 7;
@@ -11,8 +10,8 @@ main ()
{
unsigned char cy;
- cy = cx / 6; if (cy != 1) abort ();
- cy = cx % 6; if (cy != 1) abort ();
+ cy = cx / 6; if (cy != 1) exit (1);
+ cy = cx % 6; if (cy != 1) exit (1);
exit(0);
}
Index: tree-core.h
===================================================================
--- tree-core.h (revision 249057)
+++ tree-core.h (working copy)
@@ -93,6 +93,9 @@ struct die_struct;
/* Nonzero if this is an indirect call by descriptor. */
#define ECF_BY_DESCRIPTOR (1 << 14)
+/* Nonzero if this is a cold function. */
+#define ECF_COLD (1 << 15)
+
/* Call argument flags. */
/* Nonzero if the argument is not dereferenced recursively, thus only
directly reachable memory is read or written. */
Index: tree.c
===================================================================
--- tree.c (revision 249057)
+++ tree.c (working copy)
@@ -10625,6 +10625,9 @@ set_call_expr_flags (tree decl, int flag
if (flags & ECF_LEAF)
DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("leaf"),
NULL, DECL_ATTRIBUTES (decl));
+ if (flags & ECF_COLD)
+ DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("cold"),
+ NULL, DECL_ATTRIBUTES (decl));
if (flags & ECF_RET1)
DECL_ATTRIBUTES (decl)
= tree_cons (get_identifier ("fn spec"),
@@ -10674,11 +10677,11 @@ build_common_builtin_nodes (void)
BUILT_IN_UNREACHABLE,
"__builtin_unreachable",
ECF_NOTHROW | ECF_LEAF | ECF_NORETURN
- | ECF_CONST);
+ | ECF_CONST | ECF_COLD);
if (!builtin_decl_explicit_p (BUILT_IN_ABORT))
local_define_builtin ("__builtin_abort", ftype, BUILT_IN_ABORT,
"abort",
- ECF_LEAF | ECF_NORETURN | ECF_CONST);
+ ECF_LEAF | ECF_NORETURN | ECF_CONST | ECF_COLD);
}
if (!builtin_decl_explicit_p (BUILT_IN_MEMCPY)
