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re PR tree-optimization/21258 (Teach VRP to pick up a constant from case label.) 

2007-04-13  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/21258
	* tree-vrp.c (compare_case_labels): New helper.
	(find_switch_asserts): New function.
	(find_assert_locations): Call it for SWITCH_EXPRs.

	* gcc.dg/tree-ssa/vrp34.c: New testcase.

From-SVN: r123778
This commit is contained in:
Richard Guenther 2007-04-13 09:21:22 +00:00 committed by Richard Biener
parent 27ac40e2a0
commit 9bb6aa4304
4 changed files with 165 additions and 6 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2007-04-13 Richard Guenther <rguenther@suse.de>
PR tree-optimization/21258
* tree-vrp.c (compare_case_labels): New helper.
(find_switch_asserts): New function.
(find_assert_locations): Call it for SWITCH_EXPRs.
2007-04-13 Uros Bizjak <ubizjak@gmail.com>
* config/i386/i386.h (X87_FLOAT_MODE_P): Check for TARGET_80387.

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2007-04-13 Richard Guenther <rguenther@suse.de>
PR tree-optimization/21258
* gcc.dg/tree-ssa/vrp34.c: New testcase.
2007-04-12 Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
* gfortran.dg/c_by_val.c: Use GCC extensions instead of including

20
gcc/testsuite/gcc.dg/tree-ssa/vrp34.c Normal file
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@ -0,0 +1,20 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-vrp1" } */
void bar (void);
void
foo (int a)
{
switch (a)
{
case 4:
if (a >= 3)
if (a <= 5)
bar ();
}
}
/* { dg-final { scan-tree-dump "Folding predicate a_. > 2 to 1" "vrp1" } } */
/* { dg-final { scan-tree-dump "Folding predicate a_. <= 5 to 1" "vrp1" } } */
/* { dg-final { cleanup-tree-dump "vrp1" } } */

139
gcc/tree-vrp.c
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@ -3593,7 +3593,7 @@ static bool find_assert_locations (basic_block bb);
/* Determine whether the outgoing edges of BB should receive an
ASSERT_EXPR for each of the operands of BB's LAST statement.
The last statement of BB must be a COND_EXPR or a SWITCH_EXPR.
The last statement of BB must be a COND_EXPR.
If any of the sub-graphs rooted at BB have an interesting use of
the predicate operands, an assert location node is added to the
@ -3666,6 +3666,131 @@ find_conditional_asserts (basic_block bb, tree last)
return need_assert;
}
/* Compare two case labels sorting first by the destination label uid
and then by the case value. */
static int
compare_case_labels (const void *p1, const void *p2)
{
tree case1 = *(tree *)p1;
tree case2 = *(tree *)p2;
unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
if (uid1 < uid2)
return -1;
else if (uid1 == uid2)
{
/* Make sure the default label is first in a group. */
if (!CASE_LOW (case1))
return -1;
else if (!CASE_LOW (case2))
return 1;
else
return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
}
else
return 1;
}
/* Determine whether the outgoing edges of BB should receive an
ASSERT_EXPR for each of the operands of BB's LAST statement.
The last statement of BB must be a SWITCH_EXPR.
If any of the sub-graphs rooted at BB have an interesting use of
the predicate operands, an assert location node is added to the
list of assertions for the corresponding operands. */
static bool
find_switch_asserts (basic_block bb, tree last)
{
bool need_assert;
block_stmt_iterator bsi;
tree op, cond;
edge e;
tree vec = SWITCH_LABELS (last), vec2;
size_t n = TREE_VEC_LENGTH (vec);
unsigned int idx;
need_assert = false;
bsi = bsi_for_stmt (last);
op = TREE_OPERAND (last, 0);
if (TREE_CODE (op) != SSA_NAME)
return false;
/* Build a vector of case labels sorted by destination label. */
vec2 = make_tree_vec (n);
for (idx = 0; idx < n; ++idx)
TREE_VEC_ELT (vec2, idx) = TREE_VEC_ELT (vec, idx);
qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
for (idx = 0; idx < n; ++idx)
{
tree min, max;
tree cl = TREE_VEC_ELT (vec2, idx);
min = CASE_LOW (cl);
max = CASE_HIGH (cl);
/* If there are multiple case labels with the same destination
we need to combine them to a single value range for the edge. */
if (idx + 1 < n
&& CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
{
/* Skip labels until the last of the group. */
do {
++idx;
} while (idx < n
&& CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
--idx;
/* Pick up the maximum of the case label range. */
if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
else
max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
}
/* Nothing to do if the range includes the default label until we
can register anti-ranges. */
if (min == NULL_TREE)
continue;
/* Find the edge to register the assert expr on. */
e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
/* Remove the SWITCH_EXPR operand from the FOUND_IN_SUBGRAPH bitmap.
Otherwise, when we finish traversing each of the sub-graphs, we
won't know whether the variables were found in the sub-graphs or
if they had been found in a block upstream from BB. */
RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
/* Traverse the strictly dominated sub-graph rooted at E->DEST
to determine if any of the operands in the conditional
predicate are used. */
if (e->dest != bb)
need_assert |= find_assert_locations (e->dest);
/* Register the necessary assertions for the operand in the
SWITCH_EXPR. */
cond = build2 (max ? GE_EXPR : EQ_EXPR, boolean_type_node,
op, fold_convert (TREE_TYPE (op), min));
need_assert |= register_edge_assert_for (op, e, bsi, cond);
if (max)
{
cond = build2 (LE_EXPR, boolean_type_node,
op, fold_convert (TREE_TYPE (op), max));
need_assert |= register_edge_assert_for (op, e, bsi, cond);
}
}
/* Finally, indicate that we have found the operand in the
SWITCH_EXPR. */
SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
return need_assert;
}
/* Traverse all the statements in block BB looking for statements that
may generate useful assertions for the SSA names in their operand.
@ -3728,9 +3853,7 @@ find_conditional_asserts (basic_block bb, tree last)
If this function returns true, then it means that there are names
for which we need to generate ASSERT_EXPRs. Those assertions are
inserted by process_assert_insertions.
TODO. Handle SWITCH_EXPR. */
inserted by process_assert_insertions. */
static bool
find_assert_locations (basic_block bb)
@ -3853,6 +3976,11 @@ find_assert_locations (basic_block bb)
&& !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
need_assert |= find_conditional_asserts (bb, last);
if (last
&& TREE_CODE (last) == SWITCH_EXPR
&& !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
need_assert |= find_switch_asserts (bb, last);
/* Recurse into the dominator children of BB. */
for (son = first_dom_son (CDI_DOMINATORS, bb);
son;
@ -4759,8 +4887,7 @@ vrp_visit_cond_stmt (tree stmt, edge *taken_edge_p)
*taken_edge_p = NULL;
/* FIXME. Handle SWITCH_EXPRs. But first, the assert pass needs to
add ASSERT_EXPRs for them. */
/* FIXME. Handle SWITCH_EXPRs. */
if (TREE_CODE (stmt) == SWITCH_EXPR)
return SSA_PROP_VARYING;