On Mon, Jun 11, 2018 at 10:28 AM Kugan Vivekanandarajah
<kugan.vivekanandara...@linaro.org> wrote:
>
> Hi Richard,
>
> Thanks for the review and sorry for getting back to you late.
>
> On 4 June 2018 at 18:38, Richard Biener <richard.guent...@gmail.com> wrote:
> > On Mon, Jun 4, 2018 at 10:18 AM Kugan Vivekanandarajah
> > <kugan.vivekanandara...@linaro.org> wrote:
> >>
> >> Hi Richard,
> >>
> >> Thanks for the review.
> >>
> >> On 1 June 2018 at 22:20, Richard Biener <richard.guent...@gmail.com> wrote:
> >> > On Fri, Jun 1, 2018 at 4:12 AM Kugan Vivekanandarajah
> >> > <kugan.vivekanandara...@linaro.org> wrote:
> >> >>
> >> >> Hi Richard,
> >> >>
> >> >> This is the revised patch based on the review and the discussion in
> >> >> https://gcc.gnu.org/ml/gcc/2018-05/msg00179.html.
> >> >>
> >> >> In summary:
> >> >> - I skipped (element_precision (type) < element_precision (TREE_TYPE
> >> >> (@0))) in the match.pd pattern as this would prevent transformation
> >> >> for the case in PR.
> >> >> that is, I am interested in is something like:
> >> >> char t = (char) ABS_EXPR <(int) x>
> >> >> and I want to generate
> >> >> char t = (char) ABSU_EXPR <x>
> >> >>
> >> >> - I also haven't added all the necessary match.pd changes for
> >> >> ABSU_EXPR. I have a patch for that but will submit separately based on
> >> >> this reveiw.
> >> >>
> >> >> - I also tried to add ABSU_EXPRsupport in the places as necessary by
> >> >> grepping for ABS_EXPR.
> >> >>
> >> >> - I also had to add special casing in vectorizer for ABSU_EXP as its
> >> >> result is unsigned type.
> >> >>
> >> >> Is this OK. Patch bootstraps and the regression test is ongoing.
> >> >
> >> > The c/c-typeck.c:build_unary_op change looks unnecessary - the
> >> > C FE should never generate this directly (the c-common one might
> >> > be triggered by early folding I guess).
> >>
> >> The Gimple FE testcase is running into this.
> >
> > Ah, OK then.
> >
> >> >
> >> > @@ -1761,6 +1762,9 @@ const_unop (enum tree_code code, tree type, tree
> >> > arg0)
> >> > if (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) ==
> >> > REAL_CST)
> >> > return fold_abs_const (arg0, type);
> >> > break;
> >> > + case ABSU_EXPR:
> >> > + return fold_convert (type, fold_abs_const (arg0,
> >> > + signed_type_for
> >> > (type)));
> >> >
> >> > case CONJ_EXPR:
> >> >
> >> > I think this will get you bogus TREE_OVERFLOW flags set on ABSU
> >> > (-INT_MIN).
> >> >
> >> > I think you want to change fold_abs_const to properly deal with arg0
> >> > being
> >> > signed and type unsigned. That is, sth like
> >> >
> >> > diff --git a/gcc/fold-const.c b/gcc/fold-const.c
> >> > index 6f80f1b1d69..f60f9c77e91 100644
> >> > --- a/gcc/fold-const.c
> >> > +++ b/gcc/fold-const.c
> >> > @@ -13843,18 +13843,19 @@ fold_abs_const (tree arg0, tree type)
> >> > {
> >> > /* If the value is unsigned or non-negative, then the absolute
> >> > value
> >> > is the same as the ordinary value. */
> >> > - if (!wi::neg_p (wi::to_wide (arg0), TYPE_SIGN (type)))
> >> > - t = arg0;
> >> > + wide_int val = wi::to_wide (arg0);
> >> > + bool overflow = false;
> >> > + if (!wi::neg_p (val, TYPE_SIGN (TREE_TYPE (arg0))))
> >> > + ;
> >> >
> >> > /* If the value is negative, then the absolute value is
> >> > its negation. */
> >> > else
> >> > - {
> >> > - bool overflow;
> >> > - wide_int val = wi::neg (wi::to_wide (arg0), &overflow);
> >> > - t = force_fit_type (type, val, -1,
> >> > - overflow | TREE_OVERFLOW (arg0));
> >> > - }
> >> > + wide_int val = wi::neg (val, &overflow);
> >> > +
> >> > + /* Force to the destination type, set TREE_OVERFLOW for signed
> >> > + TYPE only. */
> >> > + t = force_fit_type (type, val, 1, overflow | TREE_OVERFLOW
> >> > (arg0));
> >> > }
> >> > break;
> >> >
> >> > and then simply share the const_unop code with ABS_EXPR.
> >>
> >> Done.
> >>
> >> > diff --git a/gcc/match.pd b/gcc/match.pd
> >> > index 14386da..7d7c132 100644
> >> > --- a/gcc/match.pd
> >> > +++ b/gcc/match.pd
> >> > @@ -102,6 +102,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> >> > (match (nop_convert @0)
> >> > @0)
> >> >
> >> > +(simplify (abs (convert @0))
> >> > + (if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
> >> > + && !TYPE_UNSIGNED (TREE_TYPE (@0))
> >> > + && !TYPE_UNSIGNED (type))
> >> > + (with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
> >> > + (convert (absu:utype @0)))))
> >> > +
> >> > +
> >> >
> >> > please put a comment before the pattern. I believe there's no
> >> > need to check for !TYPE_UNSIGNED (type). Note this
> >> > also converts abs ((char)int-var) to (char)absu(int-var) which
> >> > doesn't make sense. The original issue you want to address
> >> > here is the case where TYPE_PRECISION of @0 is less than
> >> > the precision of type. That is, you want to remove language
> >> > introduced integer promotion of @0 which only is possible
> >> > with ABSU. So please do add such precision check
> >> > (I simply suggested the bogus direction of the test).
> >>
> >> Done.
> >> >
> >> > diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
> >> > index 68f4fd3..9b62583 100644
> >> > --- a/gcc/tree-cfg.c
> >> > +++ b/gcc/tree-cfg.c
> >> > @@ -3685,6 +3685,12 @@ verify_gimple_assign_unary (gassign *stmt)
> >> > case PAREN_EXPR:
> >> > case CONJ_EXPR:
> >> > break;
> >> > + case ABSU_EXPR:
> >> > + if (!TYPE_UNSIGNED (lhs_type)
> >> > + || !ANY_INTEGRAL_TYPE_P (rhs1_type))
> >> >
> >> > if (!ANY_INTEGRAL_TYPE_P (lhs_type)
> >> > || !TYPE_UNSIGNED (lhs_type)
> >> > || !ANY_INTEGRAL_TYPE_P (rhs1_type)
> >> > || TYPE_UNSIGNED (rhs1_type)
> >> > || element_precision (lhs_type) != element_precision (rhs1_type))
> >> > {
> >> > error ("invalid types for ABSU_EXPR");
> >> > debug_generic_expr (lhs_type);
> >> > debug_generic_expr (rhs1_type);
> >> > return true;
> >> > }
> >> >
> >
> > ^^^ you forgot this one.
> >
> >
> >> > + return true;
> >> > + return false;
> >> > + break;
> >> >
> >> > diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c
> >> > index 30c6d9e..44b1399 100644
> >> > --- a/gcc/tree-eh.c
> >> > +++ b/gcc/tree-eh.c
> >> > @@ -2465,6 +2465,7 @@ operation_could_trap_helper_p (enum tree_code op,
> >> >
> >> > case NEGATE_EXPR:
> >> > case ABS_EXPR:
> >> > + case ABSU_EXPR:
> >> > case CONJ_EXPR:
> >> > /* These operations don't trap with floating point. */
> >> > if (honor_trapv)
> >> >
> >> > ABSU never traps. Please instead unconditionally return false.
> >> Done.
> >>
> >> >
> >> > diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
> >> > index 66c78de..b52d714 100644
> >> > --- a/gcc/tree-vect-stmts.c
> >> > +++ b/gcc/tree-vect-stmts.c
> >> > @@ -5995,7 +5995,11 @@ vectorizable_operation (gimple *stmt,
> >> > gimple_stmt_iterator *gsi,
> >> > "transform binary/unary operation.\n");
> >> >
> >> > /* Handle def. */
> >> > - vec_dest = vect_create_destination_var (scalar_dest, vectype);
> >> > + if (code == ABSU_EXPR)
> >> > + vec_dest = vect_create_destination_var (scalar_dest,
> >> > + unsigned_type_for (vectype));
> >> > + else
> >> > + vec_dest = vect_create_destination_var (scalar_dest, vectype);
> >> >
> >> > /* POINTER_DIFF_EXPR has pointer arguments which are vectorized as
> >> > vectors with unsigned elements, but the result is signed. So, we
> >> >
> >> > simply use vectype_out for creation of vec_dest.
> >> Done.
> >
> > /* Handle def. */
> > - vec_dest = vect_create_destination_var (scalar_dest, vectype);
> > + if (code == ABSU_EXPR)
> > + vec_dest = vect_create_destination_var (scalar_dest, vectype_out);
> > + else
> > + vec_dest = vect_create_destination_var (scalar_dest, vectype);
> >
> > I meant _always_ vectype_out. Thus unconditionally
> >
> > vec_dest = vect_create_destination_var (scalar_dest, vectype_out);
>
> Some testcases are failing with the changes.
>
> gcc:gcc.dg/tree-ssa/pr83329.c (internal compiler error) : This seems
> to be due to POINTER_DIFF_EXPR (?)
Ah, yes. I'd simply handle that in a more clear way.
> There is also
>
> gcc:gcc.target/i386/avx2-vshift-1.c (internal compiler error)
> gcc:gcc.target/i386/xop-vshift-1.c (internal compiler error)
>
> Example:
> /home/tcwg-buildslave/workspace/tcwg-buildfarm_2/tcwg-x86_32-build/snapshots/gcc.git~master_rev_bfa6b77/gcc/testsuite/gcc.target/i386/xop-vshift-1.c:73:1:
> error: type mismatch in binary expression^M
> vector(4) long long unsigned int^M
> ^M
> vector(4) long long int^M
> ^M
> vector(4) long long int^M
> ^M
> vect_patt_17.54_21 = vect__2.53_16 & vect_cst__20;^M
> during GIMPLE pass: vect^M
That one is odd and looks like a latent bug in pattern creation:
diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
index 507c5b94f07..6786ffcd4c6 100644
--- a/gcc/tree-vect-patterns.c
+++ b/gcc/tree-vect-patterns.c
@@ -2185,6 +2185,11 @@ vect_recog_vector_vector_shift_pattern
(vec<gimple *> *stmts,
TYPE_PRECISION (TREE_TYPE (oprnd1)));
def = vect_recog_temp_ssa_var (TREE_TYPE (rhs1), NULL);
def_stmt = gimple_build_assign (def, BIT_AND_EXPR, rhs1, mask);
+ stmt_vec_info new_stmt_info
+ = new_stmt_vec_info (def_stmt, vinfo);
+ set_vinfo_for_stmt (def_stmt, new_stmt_info);
+ STMT_VINFO_VECTYPE (new_stmt_info)
+ = get_vectype_for_scalar_type (TREE_TYPE (rhs1));
new_pattern_def_seq (stmt_vinfo, def_stmt);
}
}
I can see if I can make this change independently of yours (that is,
I'm bootstrapping
and testing the above together with an equivalent vectorizable_operation hunk).
Richard.
>
> Thanks,
> Kugan
>
>
>
> >
> > OK with those two changes.
> >
> > Thanks,
> > Richard.
> >
> >> >
> >> > diff --git a/gcc/tree.def b/gcc/tree.def
> >> > index c660b2c..5fec781 100644
> >> > --- a/gcc/tree.def
> >> > +++ b/gcc/tree.def
> >> > @@ -760,6 +760,7 @@ DEFTREECODE (MAX_EXPR, "max_expr", tcc_binary, 2)
> >> > An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE. The
> >> > operand of the ABS_EXPR must have the same type. */
> >> > DEFTREECODE (ABS_EXPR, "abs_expr", tcc_unary, 1)
> >> > +DEFTREECODE (ABSU_EXPR, "absu_expr", tcc_unary, 1)
> >> >
> >> > /* Shift operations for shift and rotate.
> >> > Shift means logical shift if done on an
> >> >
> >> > You can clearly see that the comment before ABS_EXPR doesn't apply to
> >> > ABSU_EXPR
> >> > so please add an appropriate one. I suggest
> >> >
> >> > /* Represents the unsigned absolute value of the operand.
> >> > An ABSU_EXPR must have unsigned INTEGER_TYPE. The operand of the
> >> > ABSU_EXPR
> >> > must have the corresponding signed type. */
> >>
> >> Done.
> >>
> >> Here is the reviesed patch. Is this OK?
> >>
> >> Thanks,
> >> Kugan
> >>
> >> >
> >> > Otherwise looks OK. (I didn't explicitely check for missing ABSU_EXPR
> >> > handling this time)
> >> >
> >> > Thanks,
> >> > Richard.
> >> >
> >> >
> >> >> Thanks,
> >> >> Kugan
> >> >>
> >> >>
> >> >> On 18 May 2018 at 12:36, Kugan Vivekanandarajah
> >> >> <kugan.vivekanandara...@linaro.org> wrote:
> >> >> > Hi Richard,
> >> >> >
> >> >> > Thanks for the review. I am revising the patch based on Andrew's
> >> >> > comments too.
> >> >> >
> >> >> > On 17 May 2018 at 20:36, Richard Biener <richard.guent...@gmail.com>
> >> >> > wrote:
> >> >> >> On Thu, May 17, 2018 at 4:56 AM Andrew Pinski <pins...@gmail.com>
> >> >> >> wrote:
> >> >> >>
> >> >> >>> On Wed, May 16, 2018 at 7:14 PM, Kugan Vivekanandarajah
> >> >> >>> <kugan.vivekanandara...@linaro.org> wrote:
> >> >> >>> > As mentioned in the PR, I am trying to add ABSU_EXPR to fix this
> >> >> >>> > issue. In the attached patch, in fold_cond_expr_with_comparison I
> >> >> >>> > am
> >> >> >>> > generating ABSU_EXPR for these cases. As I understand, absu_expr
> >> >> >>> > is
> >> >> >>> > well defined in RTL. So, the issue is generating absu_expr and
> >> >> >>> > transferring to RTL in the correct way. I am not sure I am not
> >> >> >>> > doing
> >> >> >>> > all that is needed. I will clean up and add more test-cases based
> >> >> >>> > on
> >> >> >>> > the feedback.
> >> >> >>
> >> >> >>
> >> >> >>> diff --git a/gcc/optabs-tree.c b/gcc/optabs-tree.c
> >> >> >>> index 71e172c..2b812e5 100644
> >> >> >>> --- a/gcc/optabs-tree.c
> >> >> >>> +++ b/gcc/optabs-tree.c
> >> >> >>> @@ -235,6 +235,7 @@ optab_for_tree_code (enum tree_code code,
> >> >> >>> const_tree
> >> >> >> type,
> >> >> >>> return trapv ? negv_optab : neg_optab;
> >> >> >>
> >> >> >>> case ABS_EXPR:
> >> >> >>> + case ABSU_EXPR:
> >> >> >>> return trapv ? absv_optab : abs_optab;
> >> >> >>
> >> >> >>
> >> >> >>> This part is not correct, it should something like this:
> >> >> >>
> >> >> >>> case ABS_EXPR:
> >> >> >>> return trapv ? absv_optab : abs_optab;
> >> >> >>> + case ABSU_EXPR:
> >> >> >>> + return abs_optab ;
> >> >> >>
> >> >> >>> Because ABSU is not undefined at the TYPE_MAX.
> >> >> >>
> >> >> >> Also
> >> >> >>
> >> >> >> /* Unsigned abs is simply the operand. Testing here means
> >> >> >> we don't
> >> >> >> risk generating incorrect code below. */
> >> >> >> - if (TYPE_UNSIGNED (type))
> >> >> >> + if (TYPE_UNSIGNED (type)
> >> >> >> + && (code != ABSU_EXPR))
> >> >> >> return op0;
> >> >> >>
> >> >> >> is wrong. ABSU of an unsigned number is still just that number.
> >> >> >>
> >> >> >> The change to fold_cond_expr_with_comparison looks odd to me
> >> >> >> (premature optimization). It should be done separately - it seems
> >> >> >> you are doing
> >> >> >
> >> >> > FE seems to be using this to generate ABS_EXPR from
> >> >> > c_fully_fold_internal to fold_build3_loc and so on. I changed this to
> >> >> > generate ABSU_EXPR for the case in the testcase. So the question
> >> >> > should be, in what cases do we need ABS_EXPR and in what cases do we
> >> >> > need ABSU_EXPR. It is not very clear to me.
> >> >> >
> >> >> >
> >> >> >>
> >> >> >> (simplify (abs (convert @0)) (convert (absu @0)))
> >> >> >>
> >> >> >> here.
> >> >> >>
> >> >> >> You touch one other place in fold-const.c but there seem to be many
> >> >> >> more that need ABSU_EXPR handling (you touched the one needed
> >> >> >> for correctness) - esp. you should at least handle constant folding
> >> >> >> in const_unop and the nonnegative predicate.
> >> >> >
> >> >> > OK.
> >> >> >>
> >> >> >> @@ -3167,6 +3167,9 @@ verify_expr (tree *tp, int *walk_subtrees,
> >> >> >> void *data
> >> >> >> ATTRIBUTE_UNUSED)
> >> >> >> CHECK_OP (0, "invalid operand to unary operator");
> >> >> >> break;
> >> >> >>
> >> >> >> + case ABSU_EXPR:
> >> >> >> + break;
> >> >> >> +
> >> >> >> case REALPART_EXPR:
> >> >> >> case IMAGPART_EXPR:
> >> >> >>
> >> >> >> verify_expr is no more. Did you test this recently against trunk?
> >> >> >
> >> >> > This patch is against slightly older trunk. I will rebase it.
> >> >> >
> >> >> >>
> >> >> >> @@ -3937,6 +3940,9 @@ verify_gimple_assign_unary (gassign *stmt)
> >> >> >> case PAREN_EXPR:
> >> >> >> case CONJ_EXPR:
> >> >> >> break;
> >> >> >> + case ABSU_EXPR:
> >> >> >> + /* FIXME. */
> >> >> >> + return false;
> >> >> >>
> >> >> >> no - please not! Please add verification here - ABSU should be only
> >> >> >> called on INTEGRAL, vector or complex INTEGRAL types and the
> >> >> >> type of the LHS should be always the unsigned variant of the
> >> >> >> argument type.
> >> >> >
> >> >> > OK.
> >> >> >>
> >> >> >> if (is_gimple_val (cond_expr))
> >> >> >> return cond_expr;
> >> >> >>
> >> >> >> - if (TREE_CODE (cond_expr) == ABS_EXPR)
> >> >> >> + if (TREE_CODE (cond_expr) == ABS_EXPR
> >> >> >> + || TREE_CODE (cond_expr) == ABSU_EXPR)
> >> >> >> {
> >> >> >> rhs1 = TREE_OPERAND (cond_expr, 1);
> >> >> >> STRIP_USELESS_TYPE_CONVERSION (rhs1);
> >> >> >>
> >> >> >> err, but the next line just builds a ABS_EXPR ...
> >> >> >>
> >> >> >> How did you identify spots that need adjustment? I would expect that
> >> >> >> once folding generates ABSU_EXPR that you need to adjust frontends
> >> >> >> (C++ constexpr handling for example). Also I miss adjustments
> >> >> >> to gimple-pretty-print.c and the GIMPLE FE parser.
> >> >> >
> >> >> > I will add this.
> >> >> >>
> >> >> >> recursively grepping throughout the whole gcc/ tree doesn't reveal
> >> >> >> too many
> >> >> >> cases of ABS_EXPR so I think it's reasonable to audit all of them.
> >> >> >>
> >> >> >> I also miss some trivial absu simplifications in match.pd. There
> >> >> >> are not
> >> >> >> a lot of abs cases but similar ones would be good to have initially.
> >> >> >
> >> >> > I will add them in the next version.
> >> >> >
> >> >> > Thanks,
> >> >> > Kugan
> >> >> >
> >> >> >>
> >> >> >> Thanks for tackling this!
> >> >> >> Richard.
> >> >> >>
> >> >> >>> Thanks,
> >> >> >>> Andrew
> >> >> >>
> >> >> >>> >
> >> >> >>> > Thanks,
> >> >> >>> > Kugan
> >> >> >>> >
> >> >> >>> >
> >> >> >>> > gcc/ChangeLog:
> >> >> >>> >
> >> >> >>> > 2018-05-13 Kugan Vivekanandarajah
> >> >> >>> > <kugan.vivekanandara...@linaro.org>
> >> >> >>> >
> >> >> >>> > * expr.c (expand_expr_real_2): Handle ABSU_EXPR.
> >> >> >>> > * fold-const.c (fold_cond_expr_with_comparison): Generate
> >> >> >>> > ABSU_EXPR
> >> >> >>> > (fold_unary_loc): Handle ABSU_EXPR.
> >> >> >>> > * optabs-tree.c (optab_for_tree_code): Likewise.
> >> >> >>> > * tree-cfg.c (verify_expr): Likewise.
> >> >> >>> > (verify_gimple_assign_unary): Likewise.
> >> >> >>> > * tree-if-conv.c (fold_build_cond_expr): Likewise.
> >> >> >>> > * tree-inline.c (estimate_operator_cost): Likewise.
> >> >> >>> > * tree-pretty-print.c (dump_generic_node): Likewise.
> >> >> >>> > * tree.def (ABSU_EXPR): New.
> >> >> >>> >
> >> >> >>> > gcc/testsuite/ChangeLog:
> >> >> >>> >
> >> >> >>> > 2018-05-13 Kugan Vivekanandarajah
> >> >> >>> > <kugan.vivekanandara...@linaro.org>
> >> >> >>> >
> >> >> >>> > * gcc.dg/absu.c: New test.
