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Re: test patch for computed gotos
Here's the entire patch, rediffed vs mainline.
r~
Index: bb-reorder.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/bb-reorder.c,v
retrieving revision 1.53
diff -c -p -d -u -r1.53 bb-reorder.c
--- bb-reorder.c 10 Feb 2003 19:18:42 -0000 1.53
+++ bb-reorder.c 11 Feb 2003 19:48:14 -0000
@@ -448,6 +448,12 @@ find_traces_1_round (branch_th, exec_th,
|| prob < branch_th || freq < exec_th || e->count < count_th)
continue;
+ /* If the destination has multiple precessesors, and can be
+ duplicated cheaper than a jump, don't allow it to be added
+ to a trace. We'll duplicate it when connecting traces. */
+ if (e->dest->pred->pred_next && copy_bb_p (e->dest, 0))
+ continue;
+
if (better_edge_p (bb, e, prob, freq, best_prob, best_freq))
{
best_edge = e;
@@ -905,19 +911,27 @@ connect_traces (n_traces, traces)
/* Try to connect the traces by duplication of 1 block. */
edge e2;
basic_block next_bb = NULL;
+ bool try_copy = false;
for (e = traces[t].last->succ; e; e = e->succ_next)
if (e->dest != EXIT_BLOCK_PTR
&& (e->flags & EDGE_CAN_FALLTHRU)
&& !(e->flags & EDGE_COMPLEX)
- && (EDGE_FREQUENCY (e) >= freq_threshold)
- && (e->count >= count_threshold)
- && (!best
- || e->probability > best->probability))
+ && (!best || e->probability > best->probability))
{
edge best2 = NULL;
int best2_len = 0;
+ /* If the destination trace is only one block
+ long, then no need to search the successor
+ blocks of the trace. Accept it. */
+ if (traces[bbd[e->dest->index].start_of_trace].length == 1)
+ {
+ best = e;
+ try_copy = true;
+ continue;
+ }
+
for (e2 = e->dest->succ; e2; e2 = e2->succ_next)
{
int di = e2->dest->index;
@@ -942,10 +956,18 @@ connect_traces (n_traces, traces)
else
best2_len = INT_MAX;
next_bb = e2->dest;
+ try_copy = true;
}
}
}
- if (best && next_bb && copy_bb_p (best->dest, !optimize_size))
+
+ /* Copy tiny blocks always; copy larger blocks only when the
+ edge is traversed frequently enough. */
+ if (try_copy
+ && copy_bb_p (best->dest,
+ !optimize_size
+ && EDGE_FREQUENCY (best) >= freq_threshold
+ && best->count >= count_threshold))
{
basic_block new_bb;
@@ -953,7 +975,9 @@ connect_traces (n_traces, traces)
{
fprintf (rtl_dump_file, "Connection: %d %d ",
traces[t].last->index, best->dest->index);
- if (next_bb == EXIT_BLOCK_PTR)
+ if (!next_bb)
+ fputc ('\n', rtl_dump_file);
+ else if (next_bb == EXIT_BLOCK_PTR)
fprintf (rtl_dump_file, "exit\n");
else
fprintf (rtl_dump_file, "%d\n", next_bb->index);
@@ -961,7 +985,7 @@ connect_traces (n_traces, traces)
new_bb = copy_bb (best->dest, best, traces[t].last, t);
traces[t].last = new_bb;
- if (next_bb != EXIT_BLOCK_PTR)
+ if (next_bb && next_bb != EXIT_BLOCK_PTR)
{
t = bbd[next_bb->index].start_of_trace;
RBI (traces[last_trace].last)->next = traces[t].first;
Index: function.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/function.c,v
retrieving revision 1.399
diff -c -p -d -u -r1.399 function.c
--- function.c 1 Feb 2003 18:59:44 -0000 1.399
+++ function.c 11 Feb 2003 19:48:15 -0000
@@ -452,6 +452,8 @@ free_after_compilation (f)
f->x_nonlocal_goto_stack_level = NULL;
f->x_cleanup_label = NULL;
f->x_return_label = NULL;
+ f->computed_goto_common_label = NULL;
+ f->computed_goto_common_reg = NULL;
f->x_save_expr_regs = NULL;
f->x_stack_slot_list = NULL;
f->x_rtl_expr_chain = NULL;
Index: function.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/function.h,v
retrieving revision 1.92
diff -c -p -d -u -r1.92 function.h
--- function.h 25 Jan 2003 17:42:38 -0000 1.92
+++ function.h 11 Feb 2003 19:48:15 -0000
@@ -268,6 +268,10 @@ struct function GTY(())
on machines which require execution of the epilogue on all returns. */
rtx x_return_label;
+ /* Label and register for unswitching computed gotos. */
+ rtx computed_goto_common_label;
+ rtx computed_goto_common_reg;
+
/* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
So we can mark them all live at the end of the function, if nonopt. */
rtx x_save_expr_regs;
Index: gcse.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/gcse.c,v
retrieving revision 1.234
diff -c -p -d -u -r1.234 gcse.c
--- gcse.c 7 Feb 2003 22:57:41 -0000 1.234
+++ gcse.c 11 Feb 2003 19:48:15 -0000
@@ -4819,7 +4819,7 @@ bypass_block (bb, setcc, jump)
if (new == pc_rtx)
dest = FALLTHRU_EDGE (bb)->dest;
else if (GET_CODE (new) == LABEL_REF)
- dest = BRANCH_EDGE (bb)->dest;
+ dest = BLOCK_FOR_INSN (XEXP (new, 0));
else
dest = NULL;
@@ -4901,7 +4901,8 @@ bypass_conditional_jumps ()
}
else if (GET_CODE (insn) == JUMP_INSN)
{
- if (any_condjump_p (insn) && onlyjump_p (insn))
+ if ((any_condjump_p (insn) || computed_jump_p (insn))
+ && onlyjump_p (insn))
changed |= bypass_block (bb, setcc, insn);
break;
}
Index: stmt.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/stmt.c,v
retrieving revision 1.289
diff -c -p -d -u -r1.289 stmt.c
--- stmt.c 25 Jan 2003 17:30:27 -0000 1.289
+++ stmt.c 11 Feb 2003 19:48:15 -0000
@@ -539,10 +539,23 @@ expand_computed_goto (exp)
#endif
emit_queue ();
- do_pending_stack_adjust ();
- emit_indirect_jump (x);
- current_function_has_computed_jump = 1;
+ if (! cfun->computed_goto_common_label)
+ {
+ cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
+ cfun->computed_goto_common_label = gen_label_rtx ();
+ emit_label (cfun->computed_goto_common_label);
+
+ do_pending_stack_adjust ();
+ emit_indirect_jump (cfun->computed_goto_common_reg);
+
+ current_function_has_computed_jump = 1;
+ }
+ else
+ {
+ emit_move_insn (cfun->computed_goto_common_reg, x);
+ emit_jump (cfun->computed_goto_common_label);
+ }
}
/* Handle goto statements and the labels that they can go to. */