On Fri, Nov 29, 2013 at 3:59 PM, Richard Sandiford
<rdsandif...@googlemail.com> wrote:
> Only a partial reply. I'll leave Kenny and Mike to answer the VARYING
> question.
>
> Richard Biener <richard.guent...@gmail.com> writes:
>> On Sat, Nov 23, 2013 at 8:23 PM, Mike Stump <mikest...@comcast.net> wrote:
>>> Richi has asked the we break the wide-int patch so that the individual
>>> port and front end maintainers can review their parts without have to
>>> go through the entire patch. This patch covers the tree-saa code.
>>>
>>> Ok?
>>
>> Same comments as to tree-affine.c apply to tree-ssa-address.c.
>>
>> @@ -887,8 +886,8 @@ copy_ref_info (tree new_ref, tree old_ref)
>> && (TREE_INT_CST_LOW (TMR_STEP (new_ref))
>> < align)))))
>> {
>> - unsigned int inc = (mem_ref_offset (old_ref)
>> - - mem_ref_offset (new_ref)).low;
>> + unsigned int inc = (mem_ref_offset (old_ref).to_uhwi ()
>> + - mem_ref_offset (new_ref).to_uhwi ());
>> adjust_ptr_info_misalignment (new_pi, inc);
>> }
>> else
>>
>> other patches used .to_short_addr (), also your conversion isn't
>> correct - previously the subtraction was in infinite precision and only
>> the result (possibly) truncated. Now the subtraction operands are
>> truncated - that looks wrong.
>
> Sorry, forgot about .to_short_addr () when doing the merge.
> The conversion should be OK with that fixed though, since truncation
> distributes through subtraction (and truncating first is cheaper).
>
>> +/* Return a widest_int that can be used for bitwise simplifications
>> from VAL. */
>>
>> -static double_int
>> -value_to_double_int (prop_value_t val)
>> +static widest_int
>> +value_to_wide_int (prop_value_t val)
>> {
>> if (val.value
>> && TREE_CODE (val.value) == INTEGER_CST)
>> - return tree_to_double_int (val.value);
>> - else
>> - return double_int_zero;
>> + return wi::to_widest (val.value);
>> +
>> + return 0;
>> }
>>
>> you also get to hope that we optimize all the widest_int return-by-value
>> code to elide the implied copying ... (not sure if you can do that by
>> adding a not implemented copy / assignment constructor - C++ folks?)
>
> Are you worried about a copy from one widest_int to another?
> Won't the return-value optimisation stop that?
If it works and applies - as far as I know this is not guaranteed. It would
be interesting to know whether any non-NRV cases are left.
> Or are you worried about the copy from the tree to the widest_int?
> In this particular case I suppose we could use:
>
> wi::to_widest (integer_zero_node)
>
> instead of 0 and return a:
>
> generic_wide_int <extended_tree <MAX_BITSIZE_MODE_ANY_INT> >
>
> (typedefed :-)). Is the function really hot enough to justify the
> uglification though? We're thinking about these kinds of tweaks now
> because it's flavour of the month, but I bet post-merge patches will
> use the more obvious implementation instead.
I wasn't worried about this specifically.
> OTOH maybe this is a natural candidate for C++11 auto...
>
>> case LT_EXPR:
>> case LE_EXPR:
>> {
>> + widest_int o1val, o2val, o1mask, o2mask;
>> int minmax, maxmin;
>> +
>> + if ((code == GE_EXPR) || (code == GT_EXPR))
>> + {
>> + o1val = r2val;
>> + o1mask = r2mask;
>> + o2val = r1val;
>> + o2mask = r1mask;
>> + code = swap_tree_comparison (code);
>> + }
>> + else
>> + {
>> + o1val = r1val;
>> + o1mask = r1mask;
>> + o2val = r2val;
>> + o2mask = r2mask;
>> + }
>>
>> that are pretty expensive copies, no? Consider using
>>
>> const widest_int &o1val = swap ? r2val : r1val;
>>
>> and so on. (C++ folks? Any idea how to avoid the repeated
>> conditional init in favor of sth that more resembles the original?)
>
> Not a C++ person, but I can't think of one either. It probably
> wouldn't be as readable as the four separate statements though.
>
>> diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c
>> index 6ea634c..c975a97 100644
>> --- a/gcc/tree-ssa-loop-im.c
>> +++ b/gcc/tree-ssa-loop-im.c
>> @@ -1643,7 +1643,7 @@ mem_refs_may_alias_p (mem_ref_p mem1, mem_ref_p mem2,
>> /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the
>> same
>> object and their offset differ in such a way that the locations cannot
>> overlap, then they cannot alias. */
>> - double_int size1, size2;
>> + widest_int size1, size2;
>> aff_tree off1, off2;
>>
>> from the names you can know this is offset_int.
>
> I agree that's true in the overlap and get_inner_reference_aff cases,
> but most of tree-affine seems to be more general than that. Is it really
> worth bunging in conversions between offset_int and widest_int to save a
> few HWIs of stack space?
I think so.
>> @@ -529,15 +526,15 @@ end:
>> difference of two values in TYPE. */
>>
>> static void
>> -bounds_add (bounds *bnds, double_int delta, tree type)
>> +bounds_add (bounds *bnds, widest_int delta, tree type)
>> {
>> mpz_t mdelta, max;
>>
>> const widest_int &delta please (please double-check the patches for
>> widest-int-by-value passing).
>>
>> @@ -2592,7 +2587,7 @@ derive_constant_upper_bound_ops (tree type, tree op0,
>>
>> static void
>> do_warn_aggressive_loop_optimizations (struct loop *loop,
>> - double_int i_bound, gimple stmt)
>> + widest_int i_bound, gimple stmt)
>> {
>> /* Don't warn if the loop doesn't have known constant bound. */
>> if (!loop->nb_iterations
>>
>> Likewise.
>
> Fixed, along with a few other cases.
>
> Testing still in progress, but does this look OK?
Yes.
Thanks,
Richard.
> Thanks,
> Richard
>
>
> Index: gcc/dwarf2out.c
> ===================================================================
> --- gcc/dwarf2out.c 2013-11-29 14:52:01.820750709 +0000
> +++ gcc/dwarf2out.c 2013-11-29 14:52:03.464763467 +0000
> @@ -14793,12 +14793,9 @@ simple_decl_align_in_bits (const_tree de
> /* Return the result of rounding T up to ALIGN. */
>
> static inline offset_int
> -round_up_to_align (offset_int t, unsigned int align)
> +round_up_to_align (const offset_int &t, unsigned int align)
> {
> - t += align - 1;
> - t = wi::udiv_trunc (t, align);
> - t *= align;
> - return t;
> + return wi::udiv_trunc (t + align - 1, align) * align;
> }
>
> /* Given a pointer to a FIELD_DECL, compute and return the byte offset of the
> Index: gcc/gimple-ssa-strength-reduction.c
> ===================================================================
> --- gcc/gimple-ssa-strength-reduction.c 2013-11-29 14:52:01.820750709 +0000
> +++ gcc/gimple-ssa-strength-reduction.c 2013-11-29 14:52:03.465763474 +0000
> @@ -2043,7 +2043,7 @@ replace_unconditional_candidate (slsr_ca
> MAX_INCR_VEC_LEN increments have been found. */
>
> static inline int
> -incr_vec_index (widest_int increment)
> +incr_vec_index (const widest_int &increment)
> {
> unsigned i;
>
> Index: gcc/tree-ssa-address.c
> ===================================================================
> --- gcc/tree-ssa-address.c 2013-11-29 14:52:01.820750709 +0000
> +++ gcc/tree-ssa-address.c 2013-11-29 14:52:03.459763428 +0000
> @@ -886,8 +886,8 @@ copy_ref_info (tree new_ref, tree old_re
> && (TREE_INT_CST_LOW (TMR_STEP (new_ref))
> < align)))))
> {
> - unsigned int inc = (mem_ref_offset (old_ref).to_uhwi ()
> - - mem_ref_offset (new_ref).to_uhwi ());
> + unsigned int inc = (mem_ref_offset (old_ref).to_short_addr ()
> + - mem_ref_offset (new_ref).to_short_addr
> ());
> adjust_ptr_info_misalignment (new_pi, inc);
> }
> else
> Index: gcc/tree-ssa-ccp.c
> ===================================================================
> --- gcc/tree-ssa-ccp.c 2013-11-29 14:52:01.820750709 +0000
> +++ gcc/tree-ssa-ccp.c 2013-11-29 14:52:03.460763435 +0000
> @@ -529,8 +529,8 @@ set_lattice_value (tree var, prop_value_
> static prop_value_t get_value_for_expr (tree, bool);
> static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree);
> static void bit_value_binop_1 (enum tree_code, tree, widest_int *,
> widest_int *,
> - tree, widest_int, widest_int,
> - tree, widest_int, widest_int);
> + tree, const widest_int &, const widest_int &,
> + tree, const widest_int &, const widest_int &);
>
> /* Return a widest_int that can be used for bitwise simplifications
> from VAL. */
> @@ -1199,11 +1199,13 @@ bit_value_unop_1 (enum tree_code code, t
> static void
> bit_value_binop_1 (enum tree_code code, tree type,
> widest_int *val, widest_int *mask,
> - tree r1type, widest_int r1val, widest_int r1mask,
> - tree r2type, widest_int r2val, widest_int r2mask)
> + tree r1type, const widest_int &r1val,
> + const widest_int &r1mask, tree r2type,
> + const widest_int &r2val, const widest_int &r2mask)
> {
> signop sgn = TYPE_SIGN (type);
> int width = TYPE_PRECISION (type);
> + bool swap_p = false;
>
> /* Assume we'll get a constant result. Use an initial non varying
> value, we fall back to varying in the end if necessary. */
> @@ -1376,27 +1378,19 @@ bit_value_binop_1 (enum tree_code code,
>
> case GE_EXPR:
> case GT_EXPR:
> + swap_p = true;
> + code = swap_tree_comparison (code);
> + /* Fall through. */
> case LT_EXPR:
> case LE_EXPR:
> {
> - widest_int o1val, o2val, o1mask, o2mask;
> int minmax, maxmin;
>
> - if ((code == GE_EXPR) || (code == GT_EXPR))
> - {
> - o1val = r2val;
> - o1mask = r2mask;
> - o2val = r1val;
> - o2mask = r1mask;
> - code = swap_tree_comparison (code);
> - }
> - else
> - {
> - o1val = r1val;
> - o1mask = r1mask;
> - o2val = r2val;
> - o2mask = r2mask;
> - }
> + const widest_int &o1val = swap_p ? r2val : r1val;
> + const widest_int &o1mask = swap_p ? r2mask : r1mask;
> + const widest_int &o2val = swap_p ? r1val : r2val;
> + const widest_int &o2mask = swap_p ? r1mask : r2mask;
> +
> /* If the most significant bits are not known we know nothing. */
> if (wi::neg_p (o1mask) || wi::neg_p (o2mask))
> break;
> Index: gcc/tree-ssa-loop-niter.c
> ===================================================================
> --- gcc/tree-ssa-loop-niter.c 2013-11-29 14:52:01.820750709 +0000
> +++ gcc/tree-ssa-loop-niter.c 2013-11-29 14:52:34.655006442 +0000
> @@ -527,7 +527,7 @@ bound_difference (struct loop *loop, tre
> difference of two values in TYPE. */
>
> static void
> -bounds_add (bounds *bnds, widest_int delta, tree type)
> +bounds_add (bounds *bnds, const widest_int &delta, tree type)
> {
> mpz_t mdelta, max;
>
> @@ -2624,10 +2624,10 @@ do_warn_aggressive_loop_optimizations (s
> is taken at last when the STMT is executed BOUND + 1 times.
> REALISTIC is true if BOUND is expected to be close to the real number
> of iterations. UPPER is true if we are sure the loop iterates at most
> - BOUND times. I_BOUND is an unsigned wide_int upper estimate on BOUND. */
> + BOUND times. I_BOUND is a widest_int upper estimate on BOUND. */
>
> static void
> -record_estimate (struct loop *loop, tree bound, widest_int i_bound,
> +record_estimate (struct loop *loop, tree bound, const widest_int &i_bound,
> gimple at_stmt, bool is_exit, bool realistic, bool upper)
> {
> widest_int delta;
> @@ -2683,15 +2683,15 @@ record_estimate (struct loop *loop, tree
> delta = 0;
> else
> delta = 1;
> - i_bound += delta;
> + widest_int new_i_bound = i_bound + delta;
>
> /* If an overflow occurred, ignore the result. */
> - if (wi::ltu_p (i_bound, delta))
> + if (wi::ltu_p (new_i_bound, delta))
> return;
>
> if (upper && !is_exit)
> - do_warn_aggressive_loop_optimizations (loop, i_bound, at_stmt);
> - record_niter_bound (loop, i_bound, realistic, upper);
> + do_warn_aggressive_loop_optimizations (loop, new_i_bound, at_stmt);
> + record_niter_bound (loop, new_i_bound, realistic, upper);
> }
>
> /* Record the estimate on number of iterations of LOOP based on the fact that
> Index: gcc/tree-vrp.c
> ===================================================================
> --- gcc/tree-vrp.c 2013-11-29 14:52:01.820750709 +0000
> +++ gcc/tree-vrp.c 2013-11-29 14:52:03.466763482 +0000
> @@ -4683,13 +4683,13 @@ extract_code_and_val_from_cond_with_ops
> SGNBIT back. */
>
> static wide_int
> -masked_increment (wide_int val, wide_int mask, wide_int sgnbit,
> - unsigned int prec)
> +masked_increment (const wide_int &val_in, const wide_int &mask,
> + const wide_int &sgnbit, unsigned int prec)
> {
> wide_int bit = wi::one (prec), res;
> unsigned int i;
>
> - val ^= sgnbit;
> + wide_int val = val_in ^ sgnbit;
> for (i = 0; i < prec; i++, bit += bit)
> {
> res = mask;
