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extended.texi (__builtin_expect): We no longer require second argument to be constant.

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* extended.texi (__builtin_expect): We no longer require second argument
	to be constant.
	* gengtype.c (adjust_field_rtx_def): Drop NOTE_INSN_EXPECTED_VALUE.
	* builtins.c (expand_builtin_expect): Simplify.
	(expand_builtin_expect_jump): Kill.
	* final.c (final_scan_insn): Do not skip the removed notes.
	* insn-notes.def (LOOP_BEG, LOOP_END, REPEATED_LINE_NUMBER,
	EXPECTED_VALUE): Remove.
	* dojump.c (do_jump): Do not care about __builtin_expect.
	* predict.c (expected_value_to_br_prob): Kill.
	* function.c (expand_function_end): Do not expand
	NOTE_INSN_REPEATED_LINE_NUMBER.
	* print-rtl.c (print_rtx): Do not pretty print the removed notes.
	* expect.c (sjlj_emit_function_enter): Emit directly branch probability.
	* cfgexpand.c (add_reg_br_prob_note): Export.
	* cfgcleanup.c (rest_of_handle_jump2): Do not call
	expected_value_to_br_prob.
	* cfglayout.c (duplicate_insn_chain): Do not deal with removed notes.
	* rtl.h (add_reg_br_prob_note): Declare.

From-SVN: r118696
This commit is contained in:
Jan Hubicka 2006-11-11 17:54:57 +01:00 • committed by Jan Hubicka
parent 89fa98d6b9
commit ef950eba66
13 changed files with 34 additions and 271 deletions
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22
gcc/ChangeLog
View file

@ -1,3 +1,25 @@
2006-11-11 Jan Hubicka <jh@suse.cz>
* extended.texi (__builtin_expect): We no longer require second argument
to be constant.
* gengtype.c (adjust_field_rtx_def): Drop NOTE_INSN_EXPECTED_VALUE.
* builtins.c (expand_builtin_expect): Simplify.
(expand_builtin_expect_jump): Kill.
* final.c (final_scan_insn): Do not skip the removed notes.
* insn-notes.def (LOOP_BEG, LOOP_END, REPEATED_LINE_NUMBER,
EXPECTED_VALUE): Remove.
* dojump.c (do_jump): Do not care about __builtin_expect.
* predict.c (expected_value_to_br_prob): Kill.
* function.c (expand_function_end): Do not expand
NOTE_INSN_REPEATED_LINE_NUMBER.
* print-rtl.c (print_rtx): Do not pretty print the removed notes.
* expect.c (sjlj_emit_function_enter): Emit directly branch probability.
* cfgexpand.c (add_reg_br_prob_note): Export.
* cfgcleanup.c (rest_of_handle_jump2): Do not call
expected_value_to_br_prob.
* cfglayout.c (duplicate_insn_chain): Do not deal with removed notes.
* rtl.h (add_reg_br_prob_note): Declare.
2006-11-11 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* tree-pretty-print.c (dump_generic_node): Print sign of Inf.

147
gcc/builtins.c
View file

@ -4693,9 +4693,9 @@ expand_builtin_fputs (tree arglist, rtx target, bool unlocked)
return 0;
}
/* Expand a call to __builtin_expect. We return our argument and emit a
NOTE_INSN_EXPECTED_VALUE note. This is the expansion of __builtin_expect in
a non-jump context. */
/* Expand a call to __builtin_expect. We just return our argument
as the builtin_expect semantic should've been already executed by
tree branch prediction pass. */
static rtx
expand_builtin_expect (tree arglist, rtx target)
@ -4709,149 +4709,12 @@ expand_builtin_expect (tree arglist, rtx target)
exp = TREE_VALUE (arglist);
c = TREE_VALUE (TREE_CHAIN (arglist));
if (TREE_CODE (c) != INTEGER_CST)
{
error ("second argument to %<__builtin_expect%> must be a constant");
c = integer_zero_node;
}
target = expand_expr (exp, target, VOIDmode, EXPAND_NORMAL);
/* Don't bother with expected value notes for integral constants. */
if (flag_guess_branch_prob && GET_CODE (target) != CONST_INT)
{
/* We do need to force this into a register so that we can be
moderately sure to be able to correctly interpret the branch
condition later. */
target = force_reg (GET_MODE (target), target);
rtx_c = expand_expr (c, NULL_RTX, GET_MODE (target), EXPAND_NORMAL);
note = emit_note (NOTE_INSN_EXPECTED_VALUE);
NOTE_EXPECTED_VALUE (note) = gen_rtx_EQ (VOIDmode, target, rtx_c);
}
/* When guessing was done, the hints should be already stripped away. */
gcc_assert (!flag_guess_branch_prob);
return target;
}
/* Like expand_builtin_expect, except do this in a jump context. This is
called from do_jump if the conditional is a __builtin_expect. Return either
a list of insns to emit the jump or NULL if we cannot optimize
__builtin_expect. We need to optimize this at jump time so that machines
like the PowerPC don't turn the test into a SCC operation, and then jump
based on the test being 0/1. */
rtx
expand_builtin_expect_jump (tree exp, rtx if_false_label, rtx if_true_label)
{
tree arglist = TREE_OPERAND (exp, 1);
tree arg0 = TREE_VALUE (arglist);
tree arg1 = TREE_VALUE (TREE_CHAIN (arglist));
rtx ret = NULL_RTX;
/* Only handle __builtin_expect (test, 0) and
__builtin_expect (test, 1). */
if (TREE_CODE (TREE_TYPE (arg1)) == INTEGER_TYPE
&& (integer_zerop (arg1) || integer_onep (arg1)))
{
rtx insn, drop_through_label, temp;
/* Expand the jump insns. */
start_sequence ();
do_jump (arg0, if_false_label, if_true_label);
ret = get_insns ();
drop_through_label = get_last_insn ();
if (drop_through_label && NOTE_P (drop_through_label))
drop_through_label = prev_nonnote_insn (drop_through_label);
if (drop_through_label && !LABEL_P (drop_through_label))
drop_through_label = NULL_RTX;
end_sequence ();
if (! if_true_label)
if_true_label = drop_through_label;
if (! if_false_label)
if_false_label = drop_through_label;
/* Go through and add the expect's to each of the conditional jumps. */
insn = ret;
while (insn != NULL_RTX)
{
rtx next = NEXT_INSN (insn);
if (JUMP_P (insn) && any_condjump_p (insn))
{
rtx ifelse = SET_SRC (pc_set (insn));
rtx then_dest = XEXP (ifelse, 1);
rtx else_dest = XEXP (ifelse, 2);
int taken = -1;
/* First check if we recognize any of the labels. */
if (GET_CODE (then_dest) == LABEL_REF
&& XEXP (then_dest, 0) == if_true_label)
taken = 1;
else if (GET_CODE (then_dest) == LABEL_REF
&& XEXP (then_dest, 0) == if_false_label)
taken = 0;
else if (GET_CODE (else_dest) == LABEL_REF
&& XEXP (else_dest, 0) == if_false_label)
taken = 1;
else if (GET_CODE (else_dest) == LABEL_REF
&& XEXP (else_dest, 0) == if_true_label)
taken = 0;
/* Otherwise check where we drop through. */
else if (else_dest == pc_rtx)
{
if (next && NOTE_P (next))
next = next_nonnote_insn (next);
if (next && JUMP_P (next)
&& any_uncondjump_p (next))
temp = XEXP (SET_SRC (pc_set (next)), 0);
else
temp = next;
/* TEMP is either a CODE_LABEL, NULL_RTX or something
else that can't possibly match either target label. */
if (temp == if_false_label)
taken = 1;
else if (temp == if_true_label)
taken = 0;
}
else if (then_dest == pc_rtx)
{
if (next && NOTE_P (next))
next = next_nonnote_insn (next);
if (next && JUMP_P (next)
&& any_uncondjump_p (next))
temp = XEXP (SET_SRC (pc_set (next)), 0);
else
temp = next;
if (temp == if_false_label)
taken = 0;
else if (temp == if_true_label)
taken = 1;
}
if (taken != -1)
{
/* If the test is expected to fail, reverse the
probabilities. */
if (integer_zerop (arg1))
taken = 1 - taken;
predict_insn_def (insn, PRED_BUILTIN_EXPECT, taken);
}
}
insn = next;
}
}
return ret;
}
void
expand_builtin_trap (void)
{

5
gcc/cfgcleanup.c
View file

@ -2300,11 +2300,6 @@ struct tree_opt_pass pass_jump =
static unsigned int
rest_of_handle_jump2 (void)
{
/* Turn NOTE_INSN_EXPECTED_VALUE into REG_BR_PROB. Do this
before jump optimization switches branch directions. */
if (flag_guess_branch_prob)
expected_value_to_br_prob ();
delete_trivially_dead_insns (get_insns (), max_reg_num ());
reg_scan (get_insns (), max_reg_num ());
if (dump_file)

2
gcc/cfgexpand.c
View file

@ -45,7 +45,7 @@ Boston, MA 02110-1301, USA. */
??? We really ought to pass the probability down to RTL expanders and let it
re-distribute it when the conditional expands into multiple conditionals.
This is however difficult to do. */
static void
void
add_reg_br_prob_note (rtx last, int probability)
{
if (profile_status == PROFILE_ABSENT)

1
gcc/cfglayout.c
View file

@ -997,7 +997,6 @@ duplicate_insn_chain (rtx from, rtx to)
case NOTE_INSN_BASIC_BLOCK:
break;
case NOTE_INSN_REPEATED_LINE_NUMBER:
case NOTE_INSN_SWITCH_TEXT_SECTIONS:
emit_note_copy (insn);
break;

7
gcc/doc/extend.texi
View file

@ -5874,10 +5874,9 @@ programmers are notoriously bad at predicting how their programs
actually perform. However, there are applications in which this
data is hard to collect.
The return value is the value of @var{exp}, which should be an
integral expression. The value of @var{c} must be a compile-time
constant. The semantics of the built-in are that it is expected
that @var{exp} == @var{c}. For example:
The return value is the value of @var{exp}, which should be an integral
expression. The semantics of the built-in are that it is expected that
@var{exp} == @var{c}. For example:
@smallexample
if (__builtin_expect (x, 0))

31
gcc/dojump.c
View file

@ -551,37 +551,6 @@ do_jump (tree exp, rtx if_false_label, rtx if_true_label)
}
break;
/* Special case:
__builtin_expect (<test>, 0) and
__builtin_expect (<test>, 1)
We need to do this here, so that <test> is not converted to a SCC
operation on machines that use condition code registers and COMPARE
like the PowerPC, and then the jump is done based on whether the SCC
operation produced a 1 or 0. */
case CALL_EXPR:
/* Check for a built-in function. */
{
tree fndecl = get_callee_fndecl (exp);
tree arglist = TREE_OPERAND (exp, 1);
if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
&& DECL_FUNCTION_CODE (fndecl) == BUILT_IN_EXPECT
&& arglist != NULL_TREE
&& TREE_CHAIN (arglist) != NULL_TREE)
{
rtx seq = expand_builtin_expect_jump (exp, if_false_label,
if_true_label);
if (seq != NULL_RTX)
{
emit_insn (seq);
return;
}
}
}
/* Fall through and generate the normal code. */
default:
normal:

4
gcc/except.c
View file

@ -1875,11 +1875,9 @@ sjlj_emit_function_enter (rtx dispatch_label)
plus_constant (XEXP (fc, 0),
sjlj_fc_jbuf_ofs), Pmode);
note = emit_note (NOTE_INSN_EXPECTED_VALUE);
NOTE_EXPECTED_VALUE (note) = gen_rtx_EQ (VOIDmode, x, const0_rtx);
emit_cmp_and_jump_insns (x, const0_rtx, NE, 0,
TYPE_MODE (integer_type_node), 0, dispatch_label);
add_reg_br_prob_note (get_insns (), REG_BR_PROB_BASE/100);
}
#else
expand_builtin_setjmp_setup (plus_constant (XEXP (fc, 0), sjlj_fc_jbuf_ofs),

2
gcc/final.c
View file

@ -1698,8 +1698,6 @@ final_scan_insn (rtx insn, FILE *file, int optimize ATTRIBUTE_UNUSED,
{
case NOTE_INSN_DELETED:
case NOTE_INSN_FUNCTION_END:
case NOTE_INSN_REPEATED_LINE_NUMBER:
case NOTE_INSN_EXPECTED_VALUE:
break;
case NOTE_INSN_SWITCH_TEXT_SECTIONS:

1
gcc/gengtype.c
View file

@ -519,7 +519,6 @@ adjust_field_rtx_def (type_p t, options_p ARG_UNUSED (opt))
note_flds = create_field (note_flds, tree_tp, "rt_tree");
break;
case NOTE_INSN_EXPECTED_VALUE:
case NOTE_INSN_VAR_LOCATION:
note_flds = create_field (note_flds, rtx_tp, "rt_rtx");
break;

73
gcc/predict.c
View file

@ -1340,79 +1340,6 @@ tree_estimate_probability (void)
return 0;
}
/* __builtin_expect dropped tokens into the insn stream describing expected
values of registers. Generate branch probabilities based off these
values. */
void
expected_value_to_br_prob (void)
{
rtx insn, cond, ev = NULL_RTX, ev_reg = NULL_RTX;
for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
{
switch (GET_CODE (insn))
{
case NOTE:
/* Look for expected value notes. */
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EXPECTED_VALUE)
{
ev = NOTE_EXPECTED_VALUE (insn);
ev_reg = XEXP (ev, 0);
delete_insn (insn);
}
continue;
case CODE_LABEL:
/* Never propagate across labels. */
ev = NULL_RTX;
continue;
case JUMP_INSN:
/* Look for simple conditional branches. If we haven't got an
expected value yet, no point going further. */
if (!JUMP_P (insn) || ev == NULL_RTX
|| ! any_condjump_p (insn))
continue;
break;
default:
/* Look for insns that clobber the EV register. */
if (ev && reg_set_p (ev_reg, insn))
ev = NULL_RTX;
continue;
}
/* Collect the branch condition, hopefully relative to EV_REG. */
/* ??? At present we'll miss things like
(expected_value (eq r70 0))
(set r71 -1)
(set r80 (lt r70 r71))
(set pc (if_then_else (ne r80 0) ...))
as canonicalize_condition will render this to us as
(lt r70, r71)
Could use cselib to try and reduce this further. */
cond = XEXP (SET_SRC (pc_set (insn)), 0);
cond = canonicalize_condition (insn, cond, 0, NULL, ev_reg,
false, false);
if (! cond || XEXP (cond, 0) != ev_reg
|| GET_CODE (XEXP (cond, 1)) != CONST_INT)
continue;
/* Substitute and simplify. Given that the expression we're
building involves two constants, we should wind up with either
true or false. */
cond = gen_rtx_fmt_ee (GET_CODE (cond), VOIDmode,
XEXP (ev, 1), XEXP (cond, 1));
cond = simplify_rtx (cond);
/* Turn the condition into a scaled branch probability. */
gcc_assert (cond == const_true_rtx || cond == const0_rtx);
predict_insn_def (insn, PRED_BUILTIN_EXPECT,
cond == const_true_rtx ? TAKEN : NOT_TAKEN);
}
}
/* Check whether this is the last basic block of function. Commonly
there is one extra common cleanup block. */
static bool

8
gcc/print-rtl.c
View file

@ -299,14 +299,6 @@ print_rtx (rtx in_rtx)
break;
}
case NOTE_INSN_EXPECTED_VALUE:
indent += 2;
if (!sawclose)
fprintf (outfile, " ");
print_rtx (NOTE_EXPECTED_VALUE (in_rtx));
indent -= 2;
break;
case NOTE_INSN_DELETED_LABEL:
{
const char *label = NOTE_DELETED_LABEL_NAME (in_rtx);

2
gcc/rtl.h
View file

@ -2250,6 +2250,8 @@ extern GTY(()) rtx stack_limit_rtx;
/* In predict.c */
extern void invert_br_probabilities (rtx);
extern bool expensive_function_p (int);
/* In cfgexpand.c */
extern void add_reg_br_prob_note (rtx last, int probability);
/* In tracer.c */
extern void tracer (unsigned int);