This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
tidy cfgexpand.c
- From: Richard Henderson <rth at twiddle dot net>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 20 Jul 2004 19:04:42 -0700
- Subject: tidy cfgexpand.c
Makes things a bit more readable. Avoids the work done to clean up
tailcalls when we won't have generated one.
r~
* cfgexpand.c (expand_gimple_cond_expr, expand_gimple_tailcall): Split,
(expand_gimple_basic_block): out from here. Renamed from expand_block.
Index: cfgexpand.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cfgexpand.c,v
retrieving revision 2.10
diff -u -p -r2.10 cfgexpand.c
--- cfgexpand.c 9 Jul 2004 03:29:26 -0000 2.10
+++ cfgexpand.c 21 Jul 2004 02:01:16 -0000
@@ -35,10 +35,159 @@ Boston, MA 02111-1307, USA. */
#include "tree-pass.h"
#include "except.h"
#include "flags.h"
+
+
+/* A subroutine of expand_gimple_basic_block. Expand one COND_EXPR.
+ Returns a new basic block if we've terminated the current basic
+ block and created a new one. */
+
+static basic_block
+expand_gimple_cond_expr (basic_block bb, tree stmt)
+{
+ basic_block new_bb, dest;
+ edge new_edge;
+ edge true_edge;
+ edge false_edge;
+ tree pred = COND_EXPR_COND (stmt);
+ tree then_exp = COND_EXPR_THEN (stmt);
+ tree else_exp = COND_EXPR_ELSE (stmt);
+ rtx last;
+
+ extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
+ if (EXPR_LOCUS (stmt))
+ {
+ emit_line_note (*(EXPR_LOCUS (stmt)));
+ record_block_change (TREE_BLOCK (stmt));
+ }
+
+ /* These flags have no purpose in RTL land. */
+ true_edge->flags &= ~EDGE_TRUE_VALUE;
+ false_edge->flags &= ~EDGE_FALSE_VALUE;
+
+ /* We can either have a pure conditional jump with one fallthru edge or
+ two-way jump that needs to be decomposed into two basic blocks. */
+ if (TREE_CODE (then_exp) == GOTO_EXPR && IS_EMPTY_STMT (else_exp))
+ {
+ jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
+ return NULL;
+ }
+ if (TREE_CODE (else_exp) == GOTO_EXPR && IS_EMPTY_STMT (then_exp))
+ {
+ jumpifnot (pred, label_rtx (GOTO_DESTINATION (else_exp)));
+ return NULL;
+ }
+ if (TREE_CODE (then_exp) != GOTO_EXPR || TREE_CODE (else_exp) != GOTO_EXPR)
+ abort ();
+
+ jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
+ last = get_last_insn ();
+ expand_expr (else_exp, const0_rtx, VOIDmode, 0);
+
+ BB_END (bb) = last;
+ if (BARRIER_P (BB_END (bb)))
+ BB_END (bb) = PREV_INSN (BB_END (bb));
+ update_bb_for_insn (bb);
+
+ new_bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
+ dest = false_edge->dest;
+ redirect_edge_succ (false_edge, new_bb);
+ false_edge->flags |= EDGE_FALLTHRU;
+ new_bb->count = false_edge->count;
+ new_bb->frequency = EDGE_FREQUENCY (false_edge);
+ new_edge = make_edge (new_bb, dest, 0);
+ new_edge->probability = REG_BR_PROB_BASE;
+ new_edge->count = new_bb->count;
+ if (BARRIER_P (BB_END (new_bb)))
+ BB_END (new_bb) = PREV_INSN (BB_END (new_bb));
+ update_bb_for_insn (new_bb);
+
+ if (dump_file)
+ {
+ dump_bb (bb, dump_file, 0);
+ dump_bb (new_bb, dump_file, 0);
+ }
+
+ return new_bb;
+}
+
+/* A subroutine of expand_gimple_basic_block. Expand one CALL_EXPR
+ that has CALL_EXPR_TAILCALL set. Returns a new basic block if we've
+ terminated the current basic block and created a new one. */
+
+static basic_block
+expand_gimple_tailcall (basic_block bb, tree stmt)
+{
+ rtx last = get_last_insn ();
+
+ expand_expr_stmt (stmt);
+
+ for (last = NEXT_INSN (last); last; last = NEXT_INSN (last))
+ {
+ if (CALL_P (last) && SIBLING_CALL_P (last))
+ {
+ edge e;
+ int probability = 0;
+ gcov_type count = 0;
+
+ do_pending_stack_adjust ();
+ e = bb->succ;
+ while (e)
+ {
+ edge next = e->succ_next;
+
+ if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
+ {
+ if (e->dest != EXIT_BLOCK_PTR)
+ {
+ e->dest->count -= e->count;
+ e->dest->frequency -= EDGE_FREQUENCY (e);
+ if (e->dest->count < 0)
+ e->dest->count = 0;
+ if (e->dest->frequency < 0)
+ e->dest->frequency = 0;
+ }
+ count += e->count;
+ probability += e->probability;
+ remove_edge (e);
+ }
+
+ e = next;
+ }
+
+ /* This is somewhat ugly: the call_expr expander often emits
+ instructions after the sibcall (to perform the function
+ return). These confuse the find_sub_basic_blocks code,
+ so we need to get rid of these. */
+ last = NEXT_INSN (last);
+ if (!BARRIER_P (last))
+ abort ();
+ while (NEXT_INSN (last))
+ {
+ /* For instance an sqrt builtin expander expands if with
+ sibcall in the then and label for `else`. */
+ if (LABEL_P (NEXT_INSN (last)))
+ break;
+ delete_insn (NEXT_INSN (last));
+ }
+ e = make_edge (bb, EXIT_BLOCK_PTR, EDGE_ABNORMAL | EDGE_SIBCALL);
+ e->probability += probability;
+ e->count += count;
+ BB_END (bb) = last;
+ update_bb_for_insn (bb);
+ if (NEXT_INSN (last))
+ bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
+ else
+ return bb;
+ }
+ }
+
+ return NULL;
+}
+
/* Expand basic block BB from GIMPLE trees to RTL. */
static basic_block
-expand_block (basic_block bb, FILE * dump_file)
+expand_gimple_basic_block (basic_block bb, FILE * dump_file)
{
block_stmt_iterator bsi = bsi_start (bb);
tree stmt = NULL;
@@ -94,157 +243,26 @@ expand_block (basic_block bb, FILE * dum
for (; !bsi_end_p (bsi); bsi_next (&bsi))
{
tree stmt = bsi_stmt (bsi);
-
- last = get_last_insn ();
+ basic_block new_bb = NULL;
if (!stmt)
continue;
/* Expand this statement, then evaluate the resulting RTL and
fixup the CFG accordingly. */
- switch (TREE_CODE (stmt))
+ if (TREE_CODE (stmt) == COND_EXPR)
+ new_bb = expand_gimple_cond_expr (bb, stmt);
+ else
{
- case COND_EXPR:
- {
- basic_block new_bb, dest;
- edge new_edge;
- edge true_edge;
- edge false_edge;
- tree pred = COND_EXPR_COND (stmt);
- tree then_exp = COND_EXPR_THEN (stmt);
- tree else_exp = COND_EXPR_ELSE (stmt);
- rtx last = get_last_insn ();
-
- extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
- if (EXPR_LOCUS (stmt))
- {
- emit_line_note (*(EXPR_LOCUS (stmt)));
- record_block_change (TREE_BLOCK (stmt));
- }
-
- /* These flags have no purpose in RTL land. */
- true_edge->flags &= ~EDGE_TRUE_VALUE;
- false_edge->flags &= ~EDGE_FALSE_VALUE;
-
- /* We can either have a pure conditional jump with one fallthru
- edge or two-way jump that needs to be decomposed into two
- basic blocks. */
- if (TREE_CODE (then_exp) == GOTO_EXPR
- && TREE_CODE (else_exp) == NOP_EXPR)
- {
- jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
- break;
- }
- if (TREE_CODE (else_exp) == GOTO_EXPR
- && TREE_CODE (then_exp) == NOP_EXPR)
- {
- jumpifnot (pred, label_rtx (GOTO_DESTINATION (else_exp)));
- break;
- }
- if (TREE_CODE (then_exp) != GOTO_EXPR
- || TREE_CODE (else_exp) != GOTO_EXPR)
- abort ();
-
- jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
- last = get_last_insn ();
- expand_expr (else_exp, const0_rtx, VOIDmode, 0);
-
- BB_END (bb) = last;
- if (BARRIER_P (BB_END (bb)))
- BB_END (bb) = PREV_INSN (BB_END (bb));
- update_bb_for_insn (bb);
-
- new_bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
- dest = false_edge->dest;
- redirect_edge_succ (false_edge, new_bb);
- false_edge->flags |= EDGE_FALLTHRU;
- new_bb->count = false_edge->count;
- new_bb->frequency = EDGE_FREQUENCY (false_edge);
- new_edge = make_edge (new_bb, dest, 0);
- new_edge->probability = REG_BR_PROB_BASE;
- new_edge->count = new_bb->count;
- if (BARRIER_P (BB_END (new_bb)))
- BB_END (new_bb) = PREV_INSN (BB_END (new_bb));
- update_bb_for_insn (new_bb);
-
- if (dump_file)
- {
- dump_bb (bb, dump_file, 0);
- dump_bb (new_bb, dump_file, 0);
- }
- return new_bb;
- }
-
- /* Update after expansion of sibling call. */
- case CALL_EXPR:
- case MODIFY_EXPR:
- case RETURN_EXPR:
- expand_expr_stmt (stmt);
- for (last = NEXT_INSN (last); last; last = NEXT_INSN (last))
- {
- if (CALL_P (last) && SIBLING_CALL_P (last))
- {
- edge e;
- int probability = 0;
- gcov_type count = 0;
-
- do_pending_stack_adjust ();
- e = bb->succ;
- while (e)
- {
- edge next = e->succ_next;
-
- if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
- {
- if (e->dest != EXIT_BLOCK_PTR)
- {
- e->dest->count -= e->count;
- e->dest->frequency -= EDGE_FREQUENCY (e);
- if (e->dest->count < 0)
- e->dest->count = 0;
- if (e->dest->frequency < 0)
- e->dest->frequency = 0;
- }
- count += e->count;
- probability += e->probability;
- remove_edge (e);
- }
-
- e = next;
- }
-
- /* This is somewhat ugly: the call_expr expander often emits instructions
- after the sibcall (to perform the function return). These confuse the
- find_sub_basic_blocks code, so we need to get rid of these. */
- last = NEXT_INSN (last);
- if (!BARRIER_P (last))
- abort ();
- while (NEXT_INSN (last))
- {
- /* For instance an sqrt builtin expander expands if with
- sibcall in the then and label for `else`. */
- if (LABEL_P (NEXT_INSN (last)))
- break;
- delete_insn (NEXT_INSN (last));
- }
- e = make_edge (bb, EXIT_BLOCK_PTR,
- EDGE_ABNORMAL | EDGE_SIBCALL);
- e->probability += probability;
- e->count += count;
- BB_END (bb) = last;
- update_bb_for_insn (bb);
- if (NEXT_INSN (last))
- bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
- else
- return bb;
- }
- }
- break;
-
- default:
- expand_expr_stmt (stmt);
- break;
+ tree call = get_call_expr_in (stmt);
+ if (call && CALL_EXPR_TAILCALL (call))
+ new_bb = expand_gimple_tailcall (bb, stmt);
+ else
+ expand_expr_stmt (stmt);
}
+
+ if (new_bb)
+ return new_bb;
}
do_pending_stack_adjust ();
@@ -261,6 +279,7 @@ expand_block (basic_block bb, FILE * dum
if (dump_file)
dump_bb (bb, dump_file, 0);
update_bb_for_insn (bb);
+
return bb;
}
@@ -332,7 +351,8 @@ construct_exit_block (void)
return;
while (NEXT_INSN (head) && NOTE_P (NEXT_INSN (head)))
head = NEXT_INSN (head);
- exit_block = create_basic_block (NEXT_INSN (head), end, EXIT_BLOCK_PTR->prev_bb);
+ exit_block = create_basic_block (NEXT_INSN (head), end,
+ EXIT_BLOCK_PTR->prev_bb);
exit_block->frequency = EXIT_BLOCK_PTR->frequency;
exit_block->count = EXIT_BLOCK_PTR->count;
for (e = EXIT_BLOCK_PTR->pred; e; e = next)
@@ -408,7 +428,7 @@ tree_expand_cfg (void)
init_block = construct_init_block ();
FOR_BB_BETWEEN (bb, init_block->next_bb, EXIT_BLOCK_PTR, next_bb)
- bb = expand_block (bb, dump_file);
+ bb = expand_gimple_basic_block (bb, dump_file);
construct_exit_block ();
@@ -448,4 +468,3 @@ struct tree_opt_pass pass_expand =
0, /* todo_flags_start */
0 /* todo_flags_finish */
};
-