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Learn CFG cleanup to transform single case switches to gcond.

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2017-09-05  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/82032
	* tree-cfg.c (generate_range_test): New function.
	* tree-cfg.h (generate_range_test): Declared here.
	* tree-cfgcleanup.c (convert_single_case_switch): New function.
	(cleanup_control_expr_graph): Use it.
	* tree-switch-conversion.c (try_switch_expansion): Remove
	assert.
	(emit_case_nodes): Use generate_range_test.
2017-09-05  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/82032
	* g++.dg/other/pr82032.C: New test.
	* gcc.dg/tree-ssa/pr68198.c: Update scanned pattern.
	* gcc.dg/tree-ssa/vrp34.c: Likewise.
	* gcc.dg/switch-10.c: Likewise.

From-SVN: r251690
This commit is contained in:
Martin Liska 2017-09-05 10:12:27 +02:00 committed by Martin Liska
parent b471c5c6cf
commit 02e637d86f
10 changed files with 144 additions and 29 deletions
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11
gcc/ChangeLog
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@ -1,3 +1,14 @@
2017-09-05 Martin Liska <mliska@suse.cz>
PR tree-optimization/82032
* tree-cfg.c (generate_range_test): New function.
* tree-cfg.h (generate_range_test): Declared here.
* tree-cfgcleanup.c (convert_single_case_switch): New function.
(cleanup_control_expr_graph): Use it.
* tree-switch-conversion.c (try_switch_expansion): Remove
assert.
(emit_case_nodes): Use generate_range_test.
2017-09-04 Uros Bizjak <ubizjak@gmail.com>
PR target/82098

8
gcc/testsuite/ChangeLog
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@ -1,3 +1,11 @@
2017-09-05 Martin Liska <mliska@suse.cz>
PR tree-optimization/82032
* g++.dg/other/pr82032.C: New test.
* gcc.dg/tree-ssa/pr68198.c: Update scanned pattern.
* gcc.dg/tree-ssa/vrp34.c: Likewise.
* gcc.dg/switch-10.c: Likewise.
2017-09-04 Uros Bizjak <ubizjak@gmail.com>
* gcc.target/i386/mpx/mpx-os-support.h: New file.

36
gcc/testsuite/g++.dg/other/pr82032.C Normal file
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@ -0,0 +1,36 @@
/* { dg-do compile } */
/* { dg-options "-O3 -Wno-return-type" } */
template <typename a> class b
{
public:
typename a::aa operator[] (typename a::c) { }
};
class d
{
public:
typedef long c;
typedef int aa;
};
struct e
{
int af[4];
int ag;
};
b<d> f;
bool
g (e &i)
{
for (int h; h; ++h)
switch (f[h])
{
case 'x':
case 'a':
i.af[h] = 3;
break;
default:
return false;
}
return true;
}

5
gcc/testsuite/gcc.dg/switch-10.c
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@ -1,6 +1,4 @@
/* { dg-options "-O2 -fdump-tree-cfg" } */
/* { dg-final { scan-tree-dump "case 0:" "cfg" } } */
/* { dg-final { scan-tree-dump-not "case 1 ... 255:" "cfg" } } */
#include <stdint.h>
void foo (void);
@ -20,3 +18,6 @@ test (uint8_t ch)
break;
}
}
/* Switch statement is converted to GIMPLE condition. */
/* { dg-final { scan-tree-dump-not "switch" "cfg" } } */

6
gcc/testsuite/gcc.dg/tree-ssa/pr68198.c
View File

@ -37,7 +37,5 @@ c_finish_omp_clauses (tree clauses)
}
}
/* There are 3 FSM jump threading opportunities, two of which will
get filtered out. */
/* { dg-final { scan-tree-dump-times "Registering FSM" 1 "thread1"} } */
/* { dg-final { scan-tree-dump-times "FSM Thread through multiway branch without threading a multiway branch" 2 "thread1"} } */
/* There are 3 FSM jump threading opportunities. */
/* { dg-final { scan-tree-dump-times "Registering FSM" 3 "thread1"} } */

5
gcc/testsuite/gcc.dg/tree-ssa/vrp34.c
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@ -15,5 +15,6 @@ foo (int a)
}
}
/* Both ifs should be optimized. */
/* { dg-final { scan-tree-dump-times "if \\\(" 0 "vrp1" } } */
/* Both ifs should be optimized (and switch statement will be the only if
in the function). */
/* { dg-final { scan-tree-dump-times "if \\\(" 1 "vrp1" } } */

24
gcc/tree-cfg.c
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@ -8927,7 +8927,31 @@ extract_true_false_controlled_edges (basic_block dom, basic_block phiblock,
return true;
}
/* Generate a range test LHS CODE RHS that determines whether INDEX is in the
range [low, high]. Place associated stmts before *GSI. */
void
generate_range_test (basic_block bb, tree index, tree low, tree high,
tree *lhs, tree *rhs)
{
tree type = TREE_TYPE (index);
tree utype = unsigned_type_for (type);
low = fold_convert (type, low);
high = fold_convert (type, high);
tree tmp = make_ssa_name (type);
gassign *sub1
= gimple_build_assign (tmp, MINUS_EXPR, index, low);
*lhs = make_ssa_name (utype);
gassign *a = gimple_build_assign (*lhs, NOP_EXPR, tmp);
*rhs = fold_build2 (MINUS_EXPR, utype, high, low);
gimple_stmt_iterator gsi = gsi_last_bb (bb);
gsi_insert_before (&gsi, sub1, GSI_SAME_STMT);
gsi_insert_before (&gsi, a, GSI_SAME_STMT);
}
/* Emit return warnings. */

2
gcc/tree-cfg.h
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@ -109,6 +109,8 @@ extern basic_block insert_cond_bb (basic_block, gimple *, gimple *,
extern bool gimple_find_sub_bbs (gimple_seq, gimple_stmt_iterator *);
extern bool extract_true_false_controlled_edges (basic_block, basic_block,
edge *, edge *);
extern void generate_range_test (basic_block bb, tree index, tree low,
tree high, tree *lhs, tree *rhs);
/* Return true if the LHS of a call should be removed. */

49
gcc/tree-cfgcleanup.c
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@ -74,6 +74,49 @@ remove_fallthru_edge (vec<edge, va_gc> *ev)
return false;
}
/* Convert a SWTCH with single non-default case to gcond and replace it
at GSI. */
static bool
convert_single_case_switch (gswitch *swtch, gimple_stmt_iterator &gsi)
{
if (gimple_switch_num_labels (swtch) != 2)
return false;
tree index = gimple_switch_index (swtch);
tree default_label = CASE_LABEL (gimple_switch_default_label (swtch));
tree label = gimple_switch_label (swtch, 1);
tree low = CASE_LOW (label);
tree high = CASE_HIGH (label);
basic_block default_bb = label_to_block_fn (cfun, default_label);
basic_block case_bb = label_to_block_fn (cfun, CASE_LABEL (label));
basic_block bb = gimple_bb (swtch);
gcond *cond;
/* Replace switch statement with condition statement. */
if (high)
{
tree lhs, rhs;
generate_range_test (bb, index, low, high, &lhs, &rhs);
cond = gimple_build_cond (LE_EXPR, lhs, rhs, NULL_TREE, NULL_TREE);
}
else
cond = gimple_build_cond (EQ_EXPR, index,
fold_convert (TREE_TYPE (index), low),
NULL_TREE, NULL_TREE);
gsi_replace (&gsi, cond, true);
/* Update edges. */
edge case_edge = find_edge (bb, case_bb);
edge default_edge = find_edge (bb, default_bb);
case_edge->flags |= EDGE_TRUE_VALUE;
default_edge->flags |= EDGE_FALSE_VALUE;
return true;
}
/* Disconnect an unreachable block in the control expression starting
at block BB. */
@ -93,6 +136,12 @@ cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi,
bool warned;
tree val = NULL_TREE;
/* Try to convert a switch with just a single non-default case to
GIMPLE condition. */
if (gimple_code (stmt) == GIMPLE_SWITCH
&& convert_single_case_switch (as_a<gswitch *> (stmt), gsi))
stmt = gsi_stmt (gsi);
fold_defer_overflow_warnings ();
switch (gimple_code (stmt))
{

27
gcc/tree-switch-conversion.c
View File

@ -2057,9 +2057,8 @@ try_switch_expansion (gswitch *stmt)
expressions being INTEGER_CST. */
gcc_assert (TREE_CODE (index_expr) != INTEGER_CST);
/* Optimization of switch statements with only one label has already
occurred, so we should never see them at this point. */
gcc_assert (ncases > 1);
if (ncases == 1)
return false;
/* Find the default case target label. */
tree default_label = CASE_LABEL (gimple_switch_default_label (stmt));
@ -2701,27 +2700,13 @@ emit_case_nodes (basic_block bb, tree index, case_node_ptr node,
}
else if (!low_bound && !high_bound)
{
tree type = TREE_TYPE (index);
tree utype = unsigned_type_for (type);
tree lhs = make_ssa_name (type);
gassign *sub1
= gimple_build_assign (lhs, MINUS_EXPR, index, node->low);
tree converted = make_ssa_name (utype);
gassign *a = gimple_build_assign (converted, NOP_EXPR, lhs);
tree rhs = fold_build2 (MINUS_EXPR, utype,
fold_convert (type, node->high),
fold_convert (type, node->low));
gimple_stmt_iterator gsi = gsi_last_bb (bb);
gsi_insert_before (&gsi, sub1, GSI_SAME_STMT);
gsi_insert_before (&gsi, a, GSI_SAME_STMT);
tree lhs, rhs;
generate_range_test (bb, index, node->low, node->high,
&lhs, &rhs);
probability
= conditional_probability (default_prob,
subtree_prob + default_prob);
bb = emit_cmp_and_jump_insns (bb, converted, rhs, GT_EXPR,
bb = emit_cmp_and_jump_insns (bb, lhs, rhs, GT_EXPR,
default_bb, probability,
phi_mapping);
}