On Tue, Jun 29, 2021 at 12:14 PM Martin Sebor via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On 6/27/21 5:24 PM, apinski--- via Gcc-patches wrote:
> > From: Andrew Pinski <apin...@marvell.com>
> >
> > To move a few things more to match-and-simplify from phiopt,
> > we need to allow match_simplify_replacement to run in early
> > phiopt. To do this we add a replacement for gimple_simplify
> > that is explictly for phiopt.
> >
> > OK? Bootstrapped and tested on x86_64-linux-gnu with no
> > regressions.
> >
> > gcc/ChangeLog:
> >
> > * tree-ssa-phiopt.c (match_simplify_replacement):
> > Add early_p argument. Call gimple_simplify_phiopt
> > instead of gimple_simplify.
> > (tree_ssa_phiopt_worker): Update call to
> > match_simplify_replacement and allow unconditionally.
> > (phiopt_early_allow): New function.
> > (gimple_simplify_phiopt): New function.
> > ---
> > gcc/tree-ssa-phiopt.c | 89 ++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 70 insertions(+), 19 deletions(-)
> >
> > diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
> > index ab12e85569d..17bc597851b 100644
> > --- a/gcc/tree-ssa-phiopt.c
> > +++ b/gcc/tree-ssa-phiopt.c
> > @@ -50,12 +50,13 @@ along with GCC; see the file COPYING3. If not see
> > #include "gimple-fold.h"
> > #include "internal-fn.h"
> > #include "gimple-range.h"
> > +#include "gimple-match.h"
> >
> > static unsigned int tree_ssa_phiopt_worker (bool, bool, bool);
> > static bool two_value_replacement (basic_block, basic_block, edge, gphi *,
> > tree, tree);
> > static bool match_simplify_replacement (basic_block, basic_block,
> > - edge, edge, gphi *, tree, tree);
> > + edge, edge, gphi *, tree, tree, bool);
> > static gphi *factor_out_conditional_conversion (edge, edge, gphi *, tree,
> > tree,
> > gimple *);
> > static int value_replacement (basic_block, basic_block,
> > @@ -345,9 +346,9 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
> > do_hoist_loads, bool early_p)
> > /* Do the replacement of conditional if it can be done. */
> > if (!early_p && two_value_replacement (bb, bb1, e2, phi, arg0,
> > arg1))
> > cfgchanged = true;
> > - else if (!early_p
> > - && match_simplify_replacement (bb, bb1, e1, e2, phi,
> > - arg0, arg1))
> > + else if (match_simplify_replacement (bb, bb1, e1, e2, phi,
> > + arg0, arg1,
> > + early_p))
> > cfgchanged = true;
> > else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
> > cfgchanged = true;
> > @@ -811,6 +812,67 @@ two_value_replacement (basic_block cond_bb,
> > basic_block middle_bb,
> > return true;
> > }
> >
> > +/* Return TRUE if CODE should be allowed during early phiopt.
> > + Currently this is to allow MIN/MAX and ABS/NEGATE. */
> > +static bool
> > +phiopt_early_allow (enum tree_code code)
> > +{
> > + switch (code)
> > + {
> > + case MIN_EXPR:
> > + case MAX_EXPR:
> > + case ABS_EXPR:
> > + case ABSU_EXPR:
> > + case NEGATE_EXPR:
> > + case SSA_NAME:
> > + return true;
> > + default:
> > + return false;
> > + }
> > +}
> > +
> > +/* gimple_simplify_phiopt is like gimple_simplify but designed for PHIOPT.
> > + Return NULL if nothing can be simplified or the resulting simplified
> > value
> > + with parts pushed if EARLY_P was true. Also rejects non allowed tree
> > code
> > + if EARLY_P is set.
> > + Takes the comparison from COMP_STMT and two args, ARG0 and ARG1 and
> > tries
> > + to simplify CMP ? ARG0 : ARG1. */
> > +static tree
> > +gimple_simplify_phiopt (bool early_p, tree type, gimple *comp_stmt,
> > + tree arg0, tree arg1,
> > + gimple_seq *seq)
> > +{
> > + tree result;
> > + enum tree_code comp_code = gimple_cond_code (comp_stmt);
> > + location_t loc = gimple_location (comp_stmt);
> > + tree cmp0 = gimple_cond_lhs (comp_stmt);
> > + tree cmp1 = gimple_cond_rhs (comp_stmt);
> > + /* To handle special cases like floating point comparison, it is easier
> > and
> > + less error-prone to build a tree and gimplify it on the fly though it
> > is
> > + less efficient.
> > + Don't use fold_build2 here as that might create (bool)a instead of
> > just
> > + "a != 0". */
> > + tree cond = build2_loc (loc, comp_code, boolean_type_node,
> > + cmp0, cmp1);
> > + gimple_match_op op (gimple_match_cond::UNCOND,
> > + COND_EXPR, type, cond, arg0, arg1);
> > +
> > + if (op.resimplify (early_p ? NULL : seq, follow_all_ssa_edges))
> > + {
> > + /* Early we want only to allow some generated tree codes. */
> > + if (!early_p
> > + || op.code.is_tree_code ()
> > + || phiopt_early_allow ((tree_code)op.code))
> > + {
> > + result = maybe_push_res_to_seq (&op, seq);
> > + if (result)
> > + return result;
>
> It looks to me like the last if statement is redundant and could
> be replaced by
>
> return maybe_push_res_to_seq (&op, seq);
>
> thus also making the result variable redundant, further simplifying
> the code.
The next patch after this one will change it anyways.
Thanks,
Andrew
>
> Martin
>
> > + }
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > /* The function match_simplify_replacement does the main work of doing
> > the
> > replacement using match and simplify. Return true if the replacement
> > is done.
> > Otherwise return false.
> > @@ -820,10 +882,9 @@ two_value_replacement (basic_block cond_bb,
> > basic_block middle_bb,
> > static bool
> > match_simplify_replacement (basic_block cond_bb, basic_block middle_bb,
> > edge e0, edge e1, gphi *phi,
> > - tree arg0, tree arg1)
> > + tree arg0, tree arg1, bool early_p)
> > {
> > gimple *stmt;
> > - tree cond;
> > gimple_stmt_iterator gsi;
> > edge true_edge, false_edge;
> > gimple_seq seq = NULL;
> > @@ -884,15 +945,6 @@ match_simplify_replacement (basic_block cond_bb,
> > basic_block middle_bb,
> >
> > stmt = last_stmt (cond_bb);
> >
> > - /* To handle special cases like floating point comparison, it is easier
> > and
> > - less error-prone to build a tree and gimplify it on the fly though it
> > is
> > - less efficient.
> > - Don't use fold_build2 here as that might create (bool)a instead of
> > just
> > - "a != 0". */
> > - cond = build2_loc (gimple_location (stmt),
> > - gimple_cond_code (stmt), boolean_type_node,
> > - gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
> > -
> > /* We need to know which is the true edge and which is the false
> > edge so that we know when to invert the condition below. */
> > extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge);
> > @@ -900,10 +952,9 @@ match_simplify_replacement (basic_block cond_bb,
> > basic_block middle_bb,
> > std::swap (arg0, arg1);
> >
> > tree type = TREE_TYPE (gimple_phi_result (phi));
> > - result = gimple_simplify (COND_EXPR, type,
> > - cond,
> > - arg0, arg1,
> > - &seq, NULL);
> > + result = gimple_simplify_phiopt (early_p, type, stmt,
> > + arg0, arg1,
> > + &seq);
> > if (!result)
> > return false;
> >
> >
>
