Hello,
This PR is again about insns that are recog'ed as >=0 but do not change the
processor state. As explained in
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52203#c8, I've tried
experimenting with an attribute marking those "empty" insns in MD files and
asserting that all other insns do have reservations. As this doesn't seem
to be interesting, I give up with the idea, and the below patch makes
sel-sched do exactly what the Haifa scheduler does, i.e. do not count such
insns against issue_rate when modelling clock cycles.
Tested on ia64 and x86-64, OK for trunk? No testcase again because of the
amount of flags needed.
Andrey
2012-03-07 Andrey Belevantsev <a...@ispras.ru>
PR rtl-optimization/52203
* sel-sched.c (estimate_insn_cost): New parameter pempty. Adjust
all callers to pass NULL except ...
(reset_sched_cycles_in_current_ebb): ... here, save the value
in new variable 'empty'. Increase issue_rate only for
non-empty insns.
diff --git a/gcc/sel-sched.c b/gcc/sel-sched.c
index 2af01ae..2829f60 100644
--- a/gcc/sel-sched.c
+++ b/gcc/sel-sched.c
@@ -4265,9 +4265,10 @@ invoke_aftermath_hooks (fence_t fence, rtx
best_insn, int issue_more)
return issue_more;
}
-/* Estimate the cost of issuing INSN on DFA state STATE. */
+/* Estimate the cost of issuing INSN on DFA state STATE. Write to PEMPTY
+ true when INSN does not change the processor state. */
static int
-estimate_insn_cost (rtx insn, state_t state)
+estimate_insn_cost (rtx insn, state_t state, bool *pempty)
{
static state_t temp = NULL;
int cost;
@@ -4277,6 +4278,8 @@ estimate_insn_cost (rtx insn, state_t state)
memcpy (temp, state, dfa_state_size);
cost = state_transition (temp, insn);
+ if (pempty)
+ *pempty = (memcmp (temp, state, dfa_state_size) == 0);
if (cost < 0)
return 0;
@@ -4307,7 +4310,7 @@ get_expr_cost (expr_t expr, fence_t fence)
return 0;
}
else
- return estimate_insn_cost (insn, FENCE_STATE (fence));
+ return estimate_insn_cost (insn, FENCE_STATE (fence), NULL);
}
/* Find the best insn for scheduling, either via max_issue or just take
@@ -7020,7 +7023,7 @@ reset_sched_cycles_in_current_ebb (void)
{
int cost, haifa_cost;
int sort_p;
- bool asm_p, real_insn, after_stall, all_issued;
+ bool asm_p, real_insn, after_stall, all_issued, empty;
int clock;
if (!INSN_P (insn))
@@ -7047,7 +7050,7 @@ reset_sched_cycles_in_current_ebb (void)
haifa_cost = 0;
}
else
- haifa_cost = estimate_insn_cost (insn, curr_state);
+ haifa_cost = estimate_insn_cost (insn, curr_state, &empty);
/* Stall for whatever cycles we've stalled before. */
after_stall = 0;
@@ -7081,7 +7084,7 @@ reset_sched_cycles_in_current_ebb (void)
if (!after_stall
&& real_insn
&& haifa_cost > 0
- && estimate_insn_cost (insn, curr_state) == 0)
+ && estimate_insn_cost (insn, curr_state, NULL) == 0)
break;
/* When the data dependency stall is longer than the DFA stall,
@@ -7093,7 +7096,7 @@ reset_sched_cycles_in_current_ebb (void)
if ((after_stall || all_issued)
&& real_insn
&& haifa_cost == 0)
- haifa_cost = estimate_insn_cost (insn, curr_state);
+ haifa_cost = estimate_insn_cost (insn, curr_state, NULL);
}
haifa_clock += i;
@@ -7125,7 +7128,8 @@ reset_sched_cycles_in_current_ebb (void)
if (real_insn)
{
cost = state_transition (curr_state, insn);
- issued_insns++;
+ if (!empty)
+ issued_insns++;
if (sched_verbose >= 2)
{
