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Leave the loop_latch basic block empty. 

2009-07-30  Sebastian Pop  <sebastian.pop@amd.com>

	* cfgloop.h (create_empty_loop_on_edge): Pass an extra argument.
	* cfgloopmanip.c (create_empty_loop_on_edge): Leave the loop_latch
	basic block empty.

From-SVN: r150293
This commit is contained in:
Sebastian Pop 2009-07-31 02:33:46 +00:00 committed by Sebastian Pop
parent 109e0d57fa
commit 8e74b39765
3 changed files with 52 additions and 40 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2009-07-30 Sebastian Pop <sebastian.pop@amd.com>
* cfgloop.h (create_empty_loop_on_edge): Pass an extra argument.
* cfgloopmanip.c (create_empty_loop_on_edge): Leave the loop_latch
basic block empty.
2009-07-30 Sebastian Pop <sebastian.pop@amd.com>
* doc/invoke.texi (-fgraphite-force-parallel): Documented.

2
gcc/cfgloop.h
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@ -283,7 +283,7 @@ extern bool can_duplicate_loop_p (const struct loop *loop);
extern edge create_empty_if_region_on_edge (edge, tree);
extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
tree *, struct loop *);
tree *, tree *, struct loop *);
extern struct loop * duplicate_loop (struct loop *, struct loop *);
extern bool duplicate_loop_to_header_edge (struct loop *, edge,
unsigned, sbitmap, edge,

84
gcc/cfgloopmanip.c
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@ -588,31 +588,35 @@ create_empty_if_region_on_edge (edge entry_edge, tree condition)
/* create_empty_loop_on_edge
|
| ------------- ------------------------
| | pred_bb | | pred_bb |
| ------------- | IV_0 = INITIAL_VALUE |
| | ------------------------
| | ______ | ENTRY_EDGE
| | ENTRY_EDGE / V V
| | ====> | -----------------------------
| | | | IV_BEFORE = phi (IV_0, IV) |
| | | | loop_header |
| V | | IV_BEFORE <= UPPER_BOUND |
| ------------- | -----------------------\-----
| | succ_bb | | | \
| ------------- | | \ exit_e
| | V V---------
| | -------------- | succ_bb |
| | | loop_latch | ----------
| | |IV = IV_BEFORE + STRIDE
| | --------------
| \ /
| \ ___ /
| - pred_bb - ------ pred_bb ------
| | | | iv0 = initial_value |
| -----|----- ---------|-----------
| | ______ | entry_edge
| | entry_edge / | |
| | ====> | -V---V- loop_header -------------
| V | | iv_before = phi (iv0, iv_after) |
| - succ_bb - | ---|-----------------------------
| | | | |
| ----------- | ---V--- loop_body ---------------
| | | iv_after = iv_before + stride |
| | | if (iv_after <= upper_bound) |
| | ---|--------------\--------------
| | | \ exit_e
| | V \
| | - loop_latch - V- succ_bb -
| | | | | |
| | /------------- -----------
| \ ___ /
Creates an empty loop as shown above, the IV_BEFORE is the SSA_NAME
that is used before the increment of IV. IV_BEFORE should be used for
adding code to the body that uses the IV. OUTER is the outer loop in
which the new loop should be inserted. */
which the new loop should be inserted.
Both INITIAL_VALUE and UPPER_BOUND expressions are gimplified and
inserted on the loop entry edge. This implies that this function
should be used only when the UPPER_BOUND expression is a loop
invariant. */
struct loop *
create_empty_loop_on_edge (edge entry_edge,
@ -620,6 +624,7 @@ create_empty_loop_on_edge (edge entry_edge,
tree stride, tree upper_bound,
tree iv,
tree *iv_before,
tree *iv_after,
struct loop *outer)
{
basic_block loop_header, loop_latch, succ_bb, pred_bb;
@ -627,13 +632,11 @@ create_empty_loop_on_edge (edge entry_edge,
int freq;
gcov_type cnt;
gimple_stmt_iterator gsi;
bool insert_after;
gimple_seq stmts;
gimple cond_expr;
tree exit_test;
edge exit_e;
int prob;
tree upper_bound_gimplified;
gcc_assert (entry_edge && initial_value && stride && upper_bound && iv);
@ -667,6 +670,11 @@ create_empty_loop_on_edge (edge entry_edge,
/* Update dominators. */
update_dominators_in_loop (loop);
/* Modify edge flags. */
exit_e = single_exit (loop);
exit_e->flags = EDGE_LOOP_EXIT | EDGE_FALSE_VALUE;
single_pred_edge (loop_latch)->flags = EDGE_TRUE_VALUE;
/* Construct IV code in loop. */
initial_value = force_gimple_operand (initial_value, &stmts, true, iv);
if (stmts)
@ -675,24 +683,20 @@ create_empty_loop_on_edge (edge entry_edge,
gsi_commit_edge_inserts ();
}
standard_iv_increment_position (loop, &gsi, &insert_after);
create_iv (initial_value, stride, iv, loop, &gsi, insert_after,
iv_before, NULL);
upper_bound = force_gimple_operand (upper_bound, &stmts, true, NULL);
if (stmts)
{
gsi_insert_seq_on_edge (loop_preheader_edge (loop), stmts);
gsi_commit_edge_inserts ();
}
/* Modify edge flags. */
exit_e = single_exit (loop);
exit_e->flags = EDGE_LOOP_EXIT | EDGE_FALSE_VALUE;
single_pred_edge (loop_latch)->flags = EDGE_TRUE_VALUE;
gsi = gsi_last_bb (loop_header);
create_iv (initial_value, stride, iv, loop, &gsi, false,
iv_before, iv_after);
gsi = gsi_last_bb (exit_e->src);
upper_bound_gimplified =
force_gimple_operand_gsi (&gsi, upper_bound, true, NULL,
false, GSI_NEW_STMT);
gsi = gsi_last_bb (exit_e->src);
cond_expr = gimple_build_cond
(LE_EXPR, *iv_before, upper_bound_gimplified, NULL_TREE, NULL_TREE);
/* Insert loop exit condition. */
cond_expr = gimple_build_cond
(LE_EXPR, *iv_after, upper_bound, NULL_TREE, NULL_TREE);
exit_test = gimple_cond_lhs (cond_expr);
exit_test = force_gimple_operand_gsi (&gsi, exit_test, true, NULL,
@ -701,6 +705,8 @@ create_empty_loop_on_edge (edge entry_edge,
gsi = gsi_last_bb (exit_e->src);
gsi_insert_after (&gsi, cond_expr, GSI_NEW_STMT);
split_block_after_labels (loop_header);
return loop;
}