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predict.c (last_basic_block_p): Remove. 

* predict.c (last_basic_block_p): Remove.
	(tree_estimate_probability): Update return heuristic for commonized
	return blocks.

From-SVN: r122367
This commit is contained in:
Jan Hubicka 2007-02-27 11:21:55 +01:00 committed by Jan Hubicka
parent e5fc6da81a
commit dcb995f769
2 changed files with 37 additions and 25 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2007-02-27 Jan Hubicka <jh@suse.cz>
* predict.c (last_basic_block_p): Remove.
(tree_estimate_probability): Update return heuristic for commonized
return blocks.
2007-02-26 Brooks Moses <brooks.moses@codesourcery.com> 2007-02-26 Brooks Moses <brooks.moses@codesourcery.com>
* Makefile.in (TEXI_GCCINSTALL_FILES): Add gcc-vers.texi dependency. * Makefile.in (TEXI_GCCINSTALL_FILES): Add gcc-vers.texi dependency.

56
gcc/predict.c
View File

@ -75,7 +75,6 @@ static sreal real_zero, real_one, real_almost_one, real_br_prob_base,
static void combine_predictions_for_insn (rtx, basic_block); static void combine_predictions_for_insn (rtx, basic_block);
static void dump_prediction (FILE *, enum br_predictor, int, basic_block, int); static void dump_prediction (FILE *, enum br_predictor, int, basic_block, int);
static void predict_paths_leading_to (basic_block, int *, enum br_predictor, enum prediction); static void predict_paths_leading_to (basic_block, int *, enum br_predictor, enum prediction);
static bool last_basic_block_p (basic_block);
static void compute_function_frequency (void); static void compute_function_frequency (void);
static void choose_function_section (void); static void choose_function_section (void);
static bool can_predict_insn_p (rtx); static bool can_predict_insn_p (rtx);
@ -1290,20 +1289,41 @@ tree_estimate_probability (void)
{ {
/* Predict early returns to be probable, as we've already taken /* Predict early returns to be probable, as we've already taken
care for error returns and other cases are often used for care for error returns and other cases are often used for
fast paths through function. */ fast paths through function.
if (e->dest == EXIT_BLOCK_PTR
&& TREE_CODE (last_stmt (bb)) == RETURN_EXPR Since we've already removed the return statments, we are
&& !single_pred_p (bb)) looking for CFG like:
if (conditoinal)
{
..
goto return_block
}
some other blocks
return_block:
return_stmt. */
if (e->dest != bb->next_bb
&& e->dest != EXIT_BLOCK_PTR
&& single_succ_p (e->dest)
&& single_succ_edge (e->dest)->dest == EXIT_BLOCK_PTR
&& TREE_CODE (last_stmt (e->dest)) == RETURN_EXPR)
{ {
edge e1; edge e1;
edge_iterator ei1; edge_iterator ei1;
FOR_EACH_EDGE (e1, ei1, bb->preds) if (single_succ_p (bb))
if (!predicted_by_p (e1->src, PRED_NULL_RETURN) {
&& !predicted_by_p (e1->src, PRED_CONST_RETURN) FOR_EACH_EDGE (e1, ei1, bb->preds)
&& !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN) if (!predicted_by_p (e1->src, PRED_NULL_RETURN)
&& !last_basic_block_p (e1->src)) && !predicted_by_p (e1->src, PRED_CONST_RETURN)
predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN); && !predicted_by_p (e1->src, PRED_NEGATIVE_RETURN))
predict_edge_def (e1, PRED_TREE_EARLY_RETURN, NOT_TAKEN);
}
else
if (!predicted_by_p (e->src, PRED_NULL_RETURN)
&& !predicted_by_p (e->src, PRED_CONST_RETURN)
&& !predicted_by_p (e->src, PRED_NEGATIVE_RETURN))
predict_edge_def (e, PRED_TREE_EARLY_RETURN, NOT_TAKEN);
} }
/* Look for block we are guarding (ie we dominate it, /* Look for block we are guarding (ie we dominate it,
@ -1353,20 +1373,6 @@ tree_estimate_probability (void)
return 0; return 0;
} }
/* Check whether this is the last basic block of function. Commonly
there is one extra common cleanup block. */
static bool
last_basic_block_p (basic_block bb)
{
if (bb == EXIT_BLOCK_PTR)
return false;
return (bb->next_bb == EXIT_BLOCK_PTR
|| (bb->next_bb->next_bb == EXIT_BLOCK_PTR
&& single_succ_p (bb)
&& single_succ (bb)->next_bb == EXIT_BLOCK_PTR));
}
/* Sets branch probabilities according to PREDiction and /* Sets branch probabilities according to PREDiction and
FLAGS. HEADS[bb->index] should be index of basic block in that we FLAGS. HEADS[bb->index] should be index of basic block in that we
need to alter branch predictions (i.e. the first of our dominators need to alter branch predictions (i.e. the first of our dominators