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-rw-r--r--gcc/tree-vrp.c192
1 files changed, 109 insertions, 83 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index c5f1468..c005c53 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -3382,6 +3382,38 @@ adjust_range_with_scev (value_range_t *vr, struct loop *loop,
else
tmax = TYPE_MAX_VALUE (type);
+ /* Try to use estimated number of iterations for the loop to constrain the
+ final value in the evolution.
+ We are interested in the number of executions of the latch, while
+ nb_iterations_upper_bound includes the last execution of the exit test. */
+ if (TREE_CODE (step) == INTEGER_CST
+ && loop->any_upper_bound
+ && !double_int_zero_p (loop->nb_iterations_upper_bound)
+ && is_gimple_val (init)
+ && (TREE_CODE (init) != SSA_NAME
+ || get_value_range (init)->type == VR_RANGE))
+ {
+ value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
+ double_int dtmp;
+ dtmp = double_int_mul (tree_to_double_int (step),
+ double_int_sub (loop->nb_iterations_upper_bound,
+ double_int_one));
+ tem = double_int_to_tree (TREE_TYPE (init), dtmp);
+ /* If the multiplication overflowed we can't do a meaningful
+ adjustment. */
+ if (double_int_equal_p (dtmp, tree_to_double_int (tem)))
+ {
+ extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
+ TREE_TYPE (init), init, tem);
+ /* Likewise if the addition did. */
+ if (maxvr.type == VR_RANGE)
+ {
+ tmin = maxvr.min;
+ tmax = maxvr.max;
+ }
+ }
+ }
+
if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
{
min = tmin;
@@ -3414,40 +3446,35 @@ adjust_range_with_scev (value_range_t *vr, struct loop *loop,
/* INIT is the maximum value. If INIT is lower than VR->MAX
but no smaller than VR->MIN, set VR->MAX to INIT. */
if (compare_values (init, max) == -1)
- {
- max = init;
-
- /* If we just created an invalid range with the minimum
- greater than the maximum, we fail conservatively.
- This should happen only in unreachable
- parts of code, or for invalid programs. */
- if (compare_values (min, max) == 1)
- return;
- }
+ max = init;
/* According to the loop information, the variable does not
overflow. If we think it does, probably because of an
overflow due to arithmetic on a different INF value,
reset now. */
- if (is_negative_overflow_infinity (min))
+ if (is_negative_overflow_infinity (min)
+ || compare_values (min, tmin) == -1)
min = tmin;
+
}
else
{
/* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
if (compare_values (init, min) == 1)
- {
- min = init;
-
- /* Again, avoid creating invalid range by failing. */
- if (compare_values (min, max) == 1)
- return;
- }
+ min = init;
- if (is_positive_overflow_infinity (max))
+ if (is_positive_overflow_infinity (max)
+ || compare_values (tmax, max) == -1)
max = tmax;
}
+ /* If we just created an invalid range with the minimum
+ greater than the maximum, we fail conservatively.
+ This should happen only in unreachable
+ parts of code, or for invalid programs. */
+ if (compare_values (min, max) == 1)
+ return;
+
set_value_range (vr, VR_RANGE, min, max, vr->equiv);
}
}
@@ -6509,8 +6536,6 @@ vrp_visit_phi_node (gimple phi)
int edges, old_edges;
struct loop *l;
- copy_value_range (&vr_result, lhs_vr);
-
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\nVisiting PHI node: ");
@@ -6571,13 +6596,6 @@ vrp_visit_phi_node (gimple phi)
}
}
- /* If this is a loop PHI node SCEV may known more about its
- value-range. */
- if (current_loops
- && (l = loop_containing_stmt (phi))
- && l->header == gimple_bb (phi))
- adjust_range_with_scev (&vr_result, l, phi, lhs);
-
if (vr_result.type == VR_VARYING)
goto varying;
@@ -6589,61 +6607,63 @@ vrp_visit_phi_node (gimple phi)
previous one. We don't do this if we have seen a new executable
edge; this helps us avoid an overflow infinity for conditionals
which are not in a loop. */
- if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
- && edges <= old_edges)
- {
- if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
- {
- int cmp_min = compare_values (lhs_vr->min, vr_result.min);
- int cmp_max = compare_values (lhs_vr->max, vr_result.max);
-
- /* If the new minimum is smaller or larger than the previous
- one, go all the way to -INF. In the first case, to avoid
- iterating millions of times to reach -INF, and in the
- other case to avoid infinite bouncing between different
- minimums. */
- if (cmp_min > 0 || cmp_min < 0)
- {
- /* If we will end up with a (-INF, +INF) range, set it to
- VARYING. Same if the previous max value was invalid for
- the type and we'd end up with vr_result.min > vr_result.max. */
- if (vrp_val_is_max (vr_result.max)
- || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
- vr_result.max) > 0)
- goto varying;
-
- if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
- || !vrp_var_may_overflow (lhs, phi))
- vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
- else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
- vr_result.min =
- negative_overflow_infinity (TREE_TYPE (vr_result.min));
- else
- goto varying;
- }
-
- /* Similarly, if the new maximum is smaller or larger than
- the previous one, go all the way to +INF. */
- if (cmp_max < 0 || cmp_max > 0)
- {
- /* If we will end up with a (-INF, +INF) range, set it to
- VARYING. Same if the previous min value was invalid for
- the type and we'd end up with vr_result.max < vr_result.min. */
- if (vrp_val_is_min (vr_result.min)
- || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
- vr_result.min) < 0)
- goto varying;
-
- if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
- || !vrp_var_may_overflow (lhs, phi))
- vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
- else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
- vr_result.max =
- positive_overflow_infinity (TREE_TYPE (vr_result.max));
- else
- goto varying;
- }
- }
+ if (edges > 0
+ && edges == old_edges)
+ {
+ int cmp_min = compare_values (lhs_vr->min, vr_result.min);
+ int cmp_max = compare_values (lhs_vr->max, vr_result.max);
+
+ /* For non VR_RANGE or for pointers fall back to varying if
+ the range changed. */
+ if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
+ || POINTER_TYPE_P (TREE_TYPE (lhs)))
+ && (cmp_min != 0 || cmp_max != 0))
+ goto varying;
+
+ /* If the new minimum is smaller or larger than the previous
+ one, go all the way to -INF. In the first case, to avoid
+ iterating millions of times to reach -INF, and in the
+ other case to avoid infinite bouncing between different
+ minimums. */
+ if (cmp_min > 0 || cmp_min < 0)
+ {
+ if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
+ || !vrp_var_may_overflow (lhs, phi))
+ vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
+ else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
+ vr_result.min =
+ negative_overflow_infinity (TREE_TYPE (vr_result.min));
+ }
+
+ /* Similarly, if the new maximum is smaller or larger than
+ the previous one, go all the way to +INF. */
+ if (cmp_max < 0 || cmp_max > 0)
+ {
+ if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
+ || !vrp_var_may_overflow (lhs, phi))
+ vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
+ else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
+ vr_result.max =
+ positive_overflow_infinity (TREE_TYPE (vr_result.max));
+ }
+
+ /* If we dropped either bound to +-INF then if this is a loop
+ PHI node SCEV may known more about its value-range. */
+ if ((cmp_min > 0 || cmp_min < 0
+ || cmp_max < 0 || cmp_max > 0)
+ && current_loops
+ && (l = loop_containing_stmt (phi))
+ && l->header == gimple_bb (phi))
+ adjust_range_with_scev (&vr_result, l, phi, lhs);
+
+ /* If we will end up with a (-INF, +INF) range, set it to
+ VARYING. Same if the previous max value was invalid for
+ the type and we end up with vr_result.min > vr_result.max. */
+ if ((vrp_val_is_max (vr_result.max)
+ && vrp_val_is_min (vr_result.min))
+ || compare_values (vr_result.min,
+ vr_result.max) > 0)
+ goto varying;
}
/* If the new range is different than the previous value, keep
@@ -7650,6 +7670,12 @@ execute_vrp (void)
rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
scev_initialize ();
+ /* Estimate number of iterations - but do not use undefined behavior
+ for this. We can't do this lazily as other functions may compute
+ this using undefined behavior. */
+ free_numbers_of_iterations_estimates ();
+ estimate_numbers_of_iterations (false);
+
insert_range_assertions ();
to_remove_edges = VEC_alloc (edge, heap, 10);
generated by cgit v1.1 at 2025-06-02 09:50:05 +0000