------- Comment #4 from hubicka at ucw dot cz 2009-07-01 10:47 -------
Subject: Re: [4.3/4.4/4.5 Regression] tracer duplicates blocks w/o adjusting
EH tree
Hi,
the following patch should prevent tracer from copying resx. It is
remarkably ugly I need to unconstify all the copy_bb_p predicates, so
perhaps I will look into fixing the RTL expanders to allow multiple RESX
blocks instead.
Index: cfghooks.c
===================================================================
--- cfghooks.c (revision 149102)
+++ cfghooks.c (working copy)
@@ -874,7 +874,7 @@ tidy_fallthru_edges (void)
/* Returns true if we can duplicate basic block BB. */
bool
-can_duplicate_block_p (const_basic_block bb)
+can_duplicate_block_p (basic_block bb)
{
if (!cfg_hooks->can_duplicate_block_p)
internal_error ("%s does not support can_duplicate_block_p",
Index: cfghooks.h
===================================================================
--- cfghooks.h (revision 149102)
+++ cfghooks.h (working copy)
@@ -75,7 +75,7 @@ struct cfg_hooks
bool (*predicted_by_p) (const_basic_block bb, enum br_predictor predictor);
/* Return true when block A can be duplicated. */
- bool (*can_duplicate_block_p) (const_basic_block a);
+ bool (*can_duplicate_block_p) (basic_block a);
/* Duplicate block A. */
basic_block (*duplicate_block) (basic_block a);
@@ -160,7 +160,7 @@ extern void tidy_fallthru_edge (edge);
extern void tidy_fallthru_edges (void);
extern void predict_edge (edge e, enum br_predictor predictor, int
probability);
extern bool predicted_by_p (const_basic_block bb, enum br_predictor
predictor);
-extern bool can_duplicate_block_p (const_basic_block);
+extern bool can_duplicate_block_p (basic_block);
extern basic_block duplicate_block (basic_block, edge, basic_block);
extern bool block_ends_with_call_p (basic_block bb);
extern bool block_ends_with_condjump_p (const_basic_block bb);
Index: bb-reorder.c
===================================================================
--- bb-reorder.c (revision 149102)
+++ bb-reorder.c (working copy)
@@ -176,7 +176,7 @@ static basic_block copy_bb (basic_block,
static fibheapkey_t bb_to_key (basic_block);
static bool better_edge_p (const_basic_block, const_edge, int, int, int, int,
const_edge);
static void connect_traces (int, struct trace *);
-static bool copy_bb_p (const_basic_block, int);
+static bool copy_bb_p (basic_block, int);
static int get_uncond_jump_length (void);
static bool push_to_next_round_p (const_basic_block, int, int, int,
gcov_type);
static void find_rarely_executed_basic_blocks_and_crossing_edges (edge **,
@@ -1157,7 +1157,7 @@ connect_traces (int n_traces, struct tra
when code size is allowed to grow by duplication. */
static bool
-copy_bb_p (const_basic_block bb, int code_may_grow)
+copy_bb_p (basic_block bb, int code_may_grow)
{
int size = 0;
int max_size = uncond_jump_length;
Index: tree-cfg.c
===================================================================
--- tree-cfg.c (revision 149102)
+++ tree-cfg.c (working copy)
@@ -5131,8 +5131,17 @@ gimple_move_block_after (basic_block bb,
/* Return true if basic_block can be duplicated. */
static bool
-gimple_can_duplicate_bb_p (const_basic_block bb ATTRIBUTE_UNUSED)
+gimple_can_duplicate_bb_p (basic_block bb)
{
+ gimple_stmt_iterator gsi = gsi_last_bb (bb);
+
+ /* RTL expander has quite artificial limitation to at most one RESX
instruction
+ per region. It can be fixed by turning 1-1 map to 1-many map, but since
the
+ code needs to be rewritten to gimple level lowering and there is little
reason
+ for duplicating RESX instructions in order to optimize code performance,
we
+ just disallow it for the moment. */
+ if (!gsi_end_p (gsi) && gimple_code (gsi_stmt (gsi)) == GIMPLE_RESX)
+ return false;
return true;
}
Index: cfgrtl.c
===================================================================
--- cfgrtl.c (revision 149102)
+++ cfgrtl.c (working copy)
@@ -3161,7 +3161,7 @@ struct cfg_hooks rtl_cfg_hooks = {
should only be used through the cfghooks interface, and we do not want to
move them here since it would require also moving quite a lot of related
code. They are in cfglayout.c. */
-extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);
+extern bool cfg_layout_can_duplicate_bb_p (basic_block);
extern basic_block cfg_layout_duplicate_bb (basic_block);
struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40585
