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Use post-dom info to update if/switch predicate

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2019-09-19  Feng Xue  <fxue@os.amperecomputing.com>

        * ipa-fnsummary.c (set_cond_stmt_execution_predicate): Do not compute
        trivial predicate for condition branch.
        (set_switch_stmt_execution_predicate): Do not compute trivial predicate
        for switch case.
        (compute_bb_predicates): Update predicate based on post-dominating
        relationship.
        (analyze_function_body): Calculate post-dominating information.

2019-09-19  Feng Xue  <fxue@os.amperecomputing.com>

        * gcc.dg/ipa/pr91089.c: Add a new function and pattern.

From-SVN: r275963
This commit is contained in:
Feng Xue 2019-09-19 14:16:01 +00:00
parent c449d3ae28
commit efe126563b
4 changed files with 128 additions and 12 deletions
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10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
2019-09-19 Feng Xue <fxue@os.amperecomputing.com>
* ipa-fnsummary.c (set_cond_stmt_execution_predicate): Do not compute
trivial predicate for condition branch.
(set_switch_stmt_execution_predicate): Do not compute trivial predicate
for switch case.
(compute_bb_predicates): Update predicate based on post-dominating
relationship.
(analyze_function_body): Calculate post-dominating information.
2019-09-19 Richard Sandiford <richard.sandiford@arm.com>
* tree-vectorizer.h (vectorizable_condition): Take an int

78
gcc/ipa-fnsummary.c
View File

@ -1197,8 +1197,14 @@ set_cond_stmt_execution_predicate (struct ipa_func_body_info *fbi,
? code : inverted_code);
/* invert_tree_comparison will return ERROR_MARK on FP
comparsions that are not EQ/NE instead of returning proper
unordered one. Be sure it is not confused with NON_CONSTANT. */
if (this_code != ERROR_MARK)
unordered one. Be sure it is not confused with NON_CONSTANT.
And if the edge's target is the final block of diamond CFG graph
of this conditional statement, we do not need to compute
predicate for the edge because the final block's predicate must
be at least as that of the first block of the statement. */
if (this_code != ERROR_MARK
&& !dominated_by_p (CDI_POST_DOMINATORS, bb, e->dest))
{
predicate p
= add_condition (summary, index, size, &aggpos, this_code,
@ -1282,18 +1288,38 @@ set_switch_stmt_execution_predicate (struct ipa_func_body_info *fbi,
*(predicate *) e->aux = false;
}
e = gimple_switch_edge (cfun, last, 0);
/* Set BOUND_COUNT to maximum count to bypass computing predicate for
default case if its target basic block is in convergence point of all
switch cases, which can be determined by checking whether it
post-dominates the switch statement. */
if (dominated_by_p (CDI_POST_DOMINATORS, bb, e->dest))
bound_count = INT_MAX;
n = gimple_switch_num_labels (last);
for (case_idx = 1; case_idx < n; ++case_idx)
{
tree cl = gimple_switch_label (last, case_idx);
tree min, max;
tree min = CASE_LOW (cl);
tree max = CASE_HIGH (cl);
predicate p;
e = gimple_switch_edge (cfun, last, case_idx);
min = CASE_LOW (cl);
max = CASE_HIGH (cl);
/* The case value might not have same type as switch expression,
extend the value based on the expression type. */
if (TREE_TYPE (min) != type)
min = wide_int_to_tree (type, wi::to_wide (min));
if (!max)
max = min;
else if (TREE_TYPE (max) != type)
max = wide_int_to_tree (type, wi::to_wide (max));
/* The case's target basic block is in convergence point of all switch
cases, its predicate should be at least as that of the switch
statement. */
if (dominated_by_p (CDI_POST_DOMINATORS, bb, e->dest))
p = true;
else if (min == max)
p = add_condition (summary, index, size, &aggpos, EQ_EXPR,
unshare_expr_without_location (min));
else
@ -1305,6 +1331,7 @@ set_switch_stmt_execution_predicate (struct ipa_func_body_info *fbi,
unshare_expr_without_location (max));
p = p1 & p2;
}
e = gimple_switch_edge (cfun, last, case_idx);
*(class predicate *) e->aux
= p.or_with (summary->conds, *(class predicate *) e->aux);
@ -1334,9 +1361,6 @@ set_switch_stmt_execution_predicate (struct ipa_func_body_info *fbi,
}
}
if (!max)
max = min;
/* Create/extend a case range. And we count endpoints of range set,
this number nearly equals to number of conditions that we will create
for predicate of default case. */
@ -1463,10 +1487,10 @@ compute_bb_predicates (struct ipa_func_body_info *fbi,
break;
}
}
if (p == false)
gcc_checking_assert (!bb->aux);
else
if (p != false)
{
basic_block pdom_bb;
if (!bb->aux)
{
done = false;
@ -1485,6 +1509,34 @@ compute_bb_predicates (struct ipa_func_body_info *fbi,
*((predicate *) bb->aux) = p;
}
}
/* For switch/if statement, we can OR-combine predicates of all
its cases/branches to get predicate for basic block in their
convergence point, but sometimes this will generate very
complicated predicate. Actually, we can get simplified
predicate in another way by using the fact that predicate
for a basic block must also hold true for its post dominators.
To be specific, basic block in convergence point of
conditional statement should include predicate of the
statement. */
pdom_bb = get_immediate_dominator (CDI_POST_DOMINATORS, bb);
if (pdom_bb == EXIT_BLOCK_PTR_FOR_FN (my_function) || !pdom_bb)
;
else if (!pdom_bb->aux)
{
done = false;
pdom_bb->aux = edge_predicate_pool.allocate ();
*((predicate *) pdom_bb->aux) = p;
}
else if (p != *(predicate *) pdom_bb->aux)
{
p = p.or_with (summary->conds, *(predicate *)pdom_bb->aux);
if (p != *(predicate *) pdom_bb->aux)
{
done = false;
*((predicate *) pdom_bb->aux) = p;
}
}
}
}
}
@ -2089,6 +2141,7 @@ analyze_function_body (struct cgraph_node *node, bool early)
if (opt_for_fn (node->decl, optimize))
{
calculate_dominance_info (CDI_DOMINATORS);
calculate_dominance_info (CDI_POST_DOMINATORS);
if (!early)
loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
else
@ -2469,6 +2522,7 @@ analyze_function_body (struct cgraph_node *node, bool early)
else if (!ipa_edge_args_sum)
ipa_free_all_node_params ();
free_dominance_info (CDI_DOMINATORS);
free_dominance_info (CDI_POST_DOMINATORS);
}
if (dump_file)
{

5
gcc/testsuite/ChangeLog
View File

@ -1,8 +1,13 @@
2019-09-19 Feng Xue <fxue@os.amperecomputing.com>
* gcc.dg/ipa/pr91089.c: Add a new function and pattern.
2019-09-19 Richard Biener <rguenther@suse.de>
PR tree-optimization/91812
* gcc.dg/torture/pr91812.c: New testcase.
>>>>>>> .r275960
2019-09-19 Tom Tromey <tromey@adacore.com>
* gnat.dg/bias1.adb: New testcase.

47
gcc/testsuite/gcc.dg/ipa/pr91089.c
View File

@ -41,6 +41,52 @@ int callee (int i)
return data += i;
}
int fn2 ();
int callee_complex_predicate (int i)
{
switch (i )
{
case 0:
fn ();
fn ();
fn ();
case 1:
fn ();
fn ();
case -1:
fn ();
case -2:
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
fn ();
data += i;
break;
}
if (i == 1000)
{
int j;
for (j = 0; j < 100; j++)
fn2 ();
}
return i + 3;
}
int caller ()
{
return callee (-127) +
@ -60,3 +106,4 @@ int caller ()
/* { dg-final { scan-ipa-dump "op0 != 0" "fnsummary" } } */
/* { dg-final { scan-ipa-dump "op0 < 5" "fnsummary" } } */
/* { dg-final { scan-ipa-dump "op0 > 7" "fnsummary" } } */
/* { dg-final { scan-ipa-dump "loop depth: 1 .+ time:\[ \]*\[0-9\]+ predicate: \\(op0 == 1000\\)\[\r\n]+" "fnsummary" } } */