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Remove conditions in the code generation of if-conversion.

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2010-05-26  Sebastian Pop  <sebastian.pop@amd.com>

	* tree-if-conv.c (tree_if_convert_cond_stmt): Do not remove
	statements in the analysis part.
	(tree_if_convert_stmt): Update comment.
	(remove_conditions_and_labels): New.
	(combine_blocks): Call remove_conditions_and_labels.
	(tree_if_conversion): Update comment.

From-SVN: r159885
This commit is contained in:
Sebastian Pop 2010-05-26 16:46:49 +00:00 • committed by Sebastian Pop
parent bc447143dc
commit 76b8477663
2 changed files with 44 additions and 31 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2010-05-26 Sebastian Pop <sebastian.pop@amd.com>
* tree-if-conv.c (tree_if_convert_cond_stmt): Do not remove
statements in the analysis part.
(tree_if_convert_stmt): Update comment.
(remove_conditions_and_labels): New.
(combine_blocks): Call remove_conditions_and_labels.
(tree_if_conversion): Update comment.
2010-05-26 Sebastian Pop <sebastian.pop@amd.com>
* tree-if-conv.c (if_convertible_bb_p): Don't handle BBs with more

66
gcc/tree-if-conv.c
View file

@ -207,7 +207,6 @@ bb_with_exit_edge_p (struct loop *loop, basic_block bb)
}
/* STMT is a GIMPLE_COND. Update two destination's predicate list.
Remove COND_EXPR, if it is not the exit condition of LOOP.
Otherwise update the exit condition of LOOP appropriately. GSI
points to the statement STMT. */
@ -232,24 +231,12 @@ tree_if_convert_cond_stmt (struct loop *loop, gimple stmt, tree cond,
/* If C is false, then FALSE_EDGE is taken. */
c2 = invert_truthvalue_loc (loc, unshare_expr (c));
add_to_dst_predicate_list (loop, false_edge, cond, c2, gsi);
/* Now this conditional statement is redundant. Remove it. But, do
not remove the exit condition! Update the exit condition using
the new condition. */
if (!bb_with_exit_edge_p (loop, gimple_bb (stmt)))
{
gsi_remove (gsi, true);
cond = NULL_TREE;
}
}
/* If-convert stmt T which is part of LOOP.
If T is a GIMPLE_ASSIGN then it is converted into a conditional
modify expression using COND. For conditional expressions, add
a condition in the destination basic block's predicate list and
remove the conditional expression itself. GSI points to the
statement T. */
For conditional expressions, add a condition in the destination
basic block's predicate list. GSI points to the statement T. */
static tree
tree_if_convert_stmt (struct loop *loop, gimple t, tree cond,
@ -286,8 +273,6 @@ tree_if_convert_stmt (struct loop *loop, gimple t, tree cond,
break;
case GIMPLE_COND:
/* Update destination blocks' predicate list and remove this
condition expression. */
tree_if_convert_cond_stmt (loop, t, cond, gsi);
cond = NULL_TREE;
break;
@ -911,6 +896,32 @@ process_phi_nodes (struct loop *loop)
}
}
/* Remove all GIMPLE_CONDs and GIMPLE_LABELs of all the basic blocks
other than the exit and latch of the LOOP. */
static void
remove_conditions_and_labels (loop_p loop)
{
gimple_stmt_iterator gsi;
unsigned int i;
for (i = 0; i < loop->num_nodes; i++)
{
basic_block bb = ifc_bbs [i];
if (bb_with_exit_edge_p (loop, bb)
|| bb == loop->latch)
continue;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
if (gimple_code (gsi_stmt (gsi)) == GIMPLE_COND
|| gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL)
gsi_remove (&gsi, true);
else
gsi_next (&gsi);
}
}
/* Combine all the basic blocks from LOOP into one or two super basic
blocks. Replace PHI nodes with conditional modify expressions. */
@ -923,6 +934,8 @@ combine_blocks (struct loop *loop)
edge e;
edge_iterator ei;
remove_conditions_and_labels (loop);
/* Process phi nodes to prepare blocks for merge. */
process_phi_nodes (loop);
@ -988,17 +1001,9 @@ combine_blocks (struct loop *loop)
if (bb == exit_bb || bb == loop->latch)
continue;
/* Remove labels and make stmts member of loop->header. */
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
{
if (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL)
gsi_remove (&gsi, true);
else
{
gimple_set_bb (gsi_stmt (gsi), merge_target_bb);
gsi_next (&gsi);
}
}
/* Make stmts member of loop->header. */
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
gimple_set_bb (gsi_stmt (gsi), merge_target_bb);
/* Update stmt list. */
last = gsi_last_bb (merge_target_bb);
@ -1049,9 +1054,8 @@ tree_if_conversion (struct loop *loop)
basic_block bb = ifc_bbs [i];
tree cond = (tree) bb->aux;
/* Process all the statements in this basic block.
Remove conditional expression, if any, and annotate
destination basic block(s) appropriately. */
/* Predicate basic block(s) with the condition expressions
leading to their execution. */
for (itr = gsi_start_bb (bb); !gsi_end_p (itr); /* empty */)
{
gimple t = gsi_stmt (itr);