On Fri, Nov 18, 2016 at 5:53 PM, Bin Cheng <[email protected]> wrote:
> Hi,
> This is a rework of https://gcc.gnu.org/ml/gcc-patches/2016-10/msg02007.html.
> Though review comments suggested it could be merged with last kind
> simplification
> of fold_cond_expr_with_comparison, it's not really applicable. As a matter
> of fact,
> the suggestion stands for patch
> @https://gcc.gnu.org/ml/gcc-patches/2016-10/msg02005.html.
> I had previous patch
> (https://gcc.gnu.org/ml/gcc-patches/2016-11/msg01898.html)
> moving fold_cond_expr_with_comparison to match.pd pattern and incorporated
> that patch into it. For this one, the rework is trivial, just renames
> several variable
> tags as suggested. Bootstrap and test on x86_64 and AArch64, is it OK?
+ A) Operand x is a unsigned to signed type conversion and c1 is
+ integer zero. In this case,
+ (signed type)x < 0 <=> x > MAX_VAL(signed type)
+ (signed type)x >= 0 <=> x <= MAX_VAL(signed type)
for (singed type)x < 0 -> x > signed-type-max we probably do a reverse
"canonicalization" transform? Yeah,
/* Non-equality compare simplifications from fold_binary */
(for cmp (lt gt le ge)
...
(if (wi::eq_p (@1, signed_max)
&& TYPE_UNSIGNED (arg1_type)
/* We will flip the signedness of the comparison operator
associated with the mode of @1, so the sign bit is
specified by this mode. Check that @1 is the signed
max associated with this sign bit. */
&& prec == GET_MODE_PRECISION (TYPE_MODE (arg1_type))
/* signed_type does not work on pointer types. */
&& INTEGRAL_TYPE_P (arg1_type))
/* The following case also applies to X < signed_max+1
and X >= signed_max+1 because previous transformations. */
(if (cmp == LE_EXPR || cmp == GT_EXPR)
(with { tree st = signed_type_for (arg1_type); }
(if (cmp == LE_EXPR)
(ge (convert:st @0) { build_zero_cst (st); })
(lt (convert:st @0) { build_zero_cst (st); }))))))))))
+ if (cmp_code == GE_EXPR)
+ cmp_code = LE_EXPR;
+ c1 = wide_int_to_tree (op_type, wi::max_value (to_type));
+ }
...
+ if (op == PLUS_EXPR)
+ real_c1 = wide_int_to_tree (op_type,
+ wi::sub (c3, c2, sgn, &overflow));
+ else
+ real_c1 = wide_int_to_tree (op_type,
+ wi::add (c3, c2, sgn, &overflow));
can you avoid the tree building here and just continue using wide-ints please?
Simply do the wide_int_to_tree in the result patterns.
Otherwise looks ok to me.
Thanks,
Richard.
> Thanks,
> bin
>
> 2016-11-17 Bin Cheng <[email protected]>
>
> * match.pd: Add new pattern:
> (cond (cmp (convert? x) c1) (op x c2) c3) -> (op (minmax x c1) c2).
>
> gcc/testsuite/ChangeLog
> 2016-11-17 Bin Cheng <[email protected]>
>
> * gcc.dg/fold-bopcond-1.c: New test.
> * gcc.dg/fold-bopcond-2.c: New test.
