bounds on the difference FINAL - IV->base. */
static bool
-number_of_iterations_ne (tree type, affine_iv *iv, tree final,
- struct tree_niter_desc *niter, bool exit_must_be_taken,
- bounds *bnds)
+number_of_iterations_ne (struct loop *loop, tree type, affine_iv *iv,
+ tree final, struct tree_niter_desc *niter,
+ bool exit_must_be_taken, bounds *bnds)
{
tree niter_type = unsigned_type_for (type);
tree s, c, d, bits, assumption, tmp, bound;
mpz_t max;
+ tree e;
niter->control = *iv;
niter->bound = final;
TYPE_SIGN (niter_type));
mpz_clear (max);
+ /* Compute no-overflow information for the control iv. Note we are
+ handling NE_EXPR, if iv base equals to final value, the loop exits
+ immediately, and the iv does not overflow. */
+ if (tree_int_cst_sign_bit (iv->step))
+ e = fold_build2 (GE_EXPR, boolean_type_node, iv->base, final);
+ else
+ e = fold_build2 (LE_EXPR, boolean_type_node, iv->base, final);
+ e = simplify_using_initial_conditions (loop, e);
+ if (integer_onep (e)
+ && (integer_onep (s)
+ || (TREE_CODE (c) == INTEGER_CST
+ && TREE_CODE (s) == INTEGER_CST
+ && wi::mod_trunc (c, s, TYPE_SIGN (type)) == 0)))
+ {
+ niter->control.no_overflow = true;
+ }
+
/* First the trivial cases -- when the step is 1. */
if (integer_onep (s))
{
that the exit must be taken eventually. */
static bool
-number_of_iterations_lt (tree type, affine_iv *iv0, affine_iv *iv1,
- struct tree_niter_desc *niter,
+number_of_iterations_lt (struct loop *loop, tree type, affine_iv *iv0,
+ affine_iv *iv1, struct tree_niter_desc *niter,
bool exit_must_be_taken, bounds *bnds)
{
tree niter_type = unsigned_type_for (type);
zps does not overflow. */
zps.no_overflow = true;
- return number_of_iterations_ne (type, &zps, delta, niter, true, bnds);
+ return number_of_iterations_ne (loop, type, &zps,
+ delta, niter, true, bnds);
}
/* Make sure that the control iv does not overflow. */
is the case). BNDS bounds the difference IV1->base - IV0->base. */
static bool
-number_of_iterations_le (tree type, affine_iv *iv0, affine_iv *iv1,
- struct tree_niter_desc *niter, bool exit_must_be_taken,
- bounds *bnds)
+number_of_iterations_le (struct loop *loop, tree type, affine_iv *iv0,
+ affine_iv *iv1, struct tree_niter_desc *niter,
+ bool exit_must_be_taken, bounds *bnds)
{
tree assumption;
tree type1 = type;
bounds_add (bnds, 1, type1);
- return number_of_iterations_lt (type, iv0, iv1, niter, exit_must_be_taken,
+ return number_of_iterations_lt (loop, type, iv0, iv1, niter, exit_must_be_taken,
bnds);
}
{
case NE_EXPR:
gcc_assert (integer_zerop (iv1->step));
- ret = number_of_iterations_ne (type, iv0, iv1->base, niter,
+ ret = number_of_iterations_ne (loop, type, iv0, iv1->base, niter,
exit_must_be_taken, &bnds);
break;
case LT_EXPR:
- ret = number_of_iterations_lt (type, iv0, iv1, niter, exit_must_be_taken,
- &bnds);
+ ret = number_of_iterations_lt (loop, type, iv0, iv1, niter,
+ exit_must_be_taken, &bnds);
break;
case LE_EXPR:
- ret = number_of_iterations_le (type, iv0, iv1, niter, exit_must_be_taken,
- &bnds);
+ ret = number_of_iterations_le (loop, type, iv0, iv1, niter,
+ exit_must_be_taken, &bnds);
break;
default: