Zdenek Dvorak <rakd...@kam.mff.cuni.cz> wrote on 05/07/2011 13:37:41:
> From: Zdenek Dvorak <rakd...@kam.mff.cuni.cz>
> To: Razya Ladelsky/Haifa/IBM@IBMIL
> Cc: gcc-patches@gcc.gnu.org, Richard Guenther
<richard.guent...@gmail.com>
> Date: 05/07/2011 13:37
> Subject: Re: PATCH] PR 49580
>
> Hi,
>
> > I moved the adjustment of the loop's iterations from
> > gimple_duplicate_sese_tail
> > to tree-parloops.c, right before the call to
gimple_duplicate_sese_tail.
> > I repeated the bootstrap, regression and spec runs - no new
regressions.
> >
> > OK to commit?
>
> OK,
>
> Zdenek
I also want to commit this testcase, which is a reduced case of the gcc
benchmark.
I apologize for not submitting it together with the patch.
OK?
Thanks,
Razya
>
> > Index: gcc/tree-parloops.c
> > ===================================================================
> > --- gcc/tree-parloops.c (revision 174166)
> > +++ gcc/tree-parloops.c (working copy)
> > @@ -1464,6 +1464,8 @@ transform_to_exit_first_loop (struct loop *loop,
h
> > gimple phi, nphi, cond_stmt, stmt, cond_nit;
> > gimple_stmt_iterator gsi;
> > tree nit_1;
> > + edge exit_1;
> > + tree new_rhs;
> >
> > split_block_after_labels (loop->header);
> > orig_header = single_succ (loop->header);
> > @@ -1492,6 +1494,38 @@ transform_to_exit_first_loop (struct loop
*loop, h
> > control = t;
> > }
> > }
> > +
> > + /* Setting the condition towards peeling the last iteration:
> > + If the block consisting of the exit condition has the latch as
> > + successor, then the body of the loop is executed before
> > + the exit condition is tested. In such case, moving the
> > + condition to the entry, causes that the loop will iterate
> > + one less iteration (which is the wanted outcome, since we
> > + peel out the last iteration). If the body is executed after
> > + the condition, moving the condition to the entry requires
> > + decrementing one iteration. */
> > + exit_1 = EDGE_SUCC (exit->src, EDGE_SUCC (exit->src, 0) == exit);
> > + if (exit_1->dest == loop->latch)
> > + new_rhs = gimple_cond_rhs (cond_stmt);
> > + else
> > + {
> > + new_rhs = fold_build2 (MINUS_EXPR, TREE_TYPE (gimple_cond_rhs
> (cond_stmt)),
> > + gimple_cond_rhs (cond_stmt),
> > + build_int_cst (TREE_TYPE (gimple_cond_rhs (cond_stmt)),
1));
> > + if (TREE_CODE (gimple_cond_rhs (cond_stmt)) == SSA_NAME)
> > + {
> > + basic_block preheader;
> > + gimple_stmt_iterator gsi1;
> > +
> > + preheader = loop_preheader_edge(loop)->src;
> > + gsi1 = gsi_after_labels (preheader);
> > + new_rhs = force_gimple_operand_gsi (&gsi1, new_rhs, true,
> > + NULL_TREE,false,GSI_CONTINUE_LINKING);
> > + }
> > + }
> > + gimple_cond_set_rhs (cond_stmt, unshare_expr (new_rhs));
> > + gimple_cond_set_lhs (cond_stmt, unshare_expr (gimple_cond_lhs
> (cond_stmt)));
> > +
> > bbs = get_loop_body_in_dom_order (loop);
> >
> > for (n = 0; bbs[n] != loop->latch; n++)
> > Index: gcc/tree-cfg.c
> > ===================================================================
> > --- gcc/tree-cfg.c (revision 174166)
> > +++ gcc/tree-cfg.c (working copy)
> > @@ -5397,12 +5397,10 @@ gimple_duplicate_sese_tail (edge entry
ATTRIBUTE_U
> > int total_freq = 0, exit_freq = 0;
> > gcov_type total_count = 0, exit_count = 0;
> > edge exits[2], nexits[2], e;
> > - gimple_stmt_iterator gsi,gsi1;
> > + gimple_stmt_iterator gsi;
> > gimple cond_stmt;
> > edge sorig, snew;
> > basic_block exit_bb;
> > - basic_block iters_bb;
> > - tree new_rhs;
> > gimple_stmt_iterator psi;
> > gimple phi;
> > tree def;
> > @@ -5483,35 +5481,6 @@ gimple_duplicate_sese_tail (edge entry
ATTRIBUTE_U
> > gcc_assert (gimple_code (cond_stmt) == GIMPLE_COND);
> > cond_stmt = gimple_copy (cond_stmt);
> >
> > - /* If the block consisting of the exit condition has the latch as
> > - successor, then the body of the loop is executed before
> > - the exit condition is tested. In such case, moving the
> > - condition to the entry, causes that the loop will iterate
> > - one less iteration (which is the wanted outcome, since we
> > - peel out the last iteration). If the body is executed after
> > - the condition, moving the condition to the entry requires
> > - decrementing one iteration. */
> > - if (exits[1]->dest == orig_loop->latch)
> > - new_rhs = gimple_cond_rhs (cond_stmt);
> > - else
> > - {
> > - new_rhs = fold_build2 (MINUS_EXPR, TREE_TYPE (gimple_cond_rhs
> (cond_stmt)),
> > - gimple_cond_rhs (cond_stmt),
> > - build_int_cst (TREE_TYPE (gimple_cond_rhs (cond_stmt)),
1));
> > -
> > - if (TREE_CODE (gimple_cond_rhs (cond_stmt)) == SSA_NAME)
> > - {
> > - iters_bb = gimple_bb (SSA_NAME_DEF_STMT (gimple_cond_rhs
(cond_stmt)));
> > - for (gsi1 = gsi_start_bb (iters_bb); !gsi_end_p (gsi1);
> gsi_next (&gsi1))
> > - if (gsi_stmt (gsi1) == SSA_NAME_DEF_STMT (gimple_cond_rhs
> (cond_stmt)))
> > - break;
> > -
> > - new_rhs = force_gimple_operand_gsi (&gsi1, new_rhs, true,
> > - NULL_TREE,false,GSI_CONTINUE_LINKING);
> > - }
> > - }
> > - gimple_cond_set_rhs (cond_stmt, unshare_expr (new_rhs));
> > - gimple_cond_set_lhs (cond_stmt, unshare_expr (gimple_cond_lhs
> (cond_stmt)));
> > gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT);
> >
> > sorig = single_succ_edge (switch_bb);
>
> >
> > 07-05-2011 Razya Ladelsky <ra...@il.ibm.com>
> >
> > * tree-cfg.c (gimple_duplicate_sese_tail): Remove handling of
> > the loop's number of iterations.
> > * tree-parloops.c (transform_to_exit_first_loop): Add the
> > handling of the loop's number of iterations before the call
> > to gimple_duplicate_sese_tail.
> > Insert the stmt caclculating the new rhs of the loop's
> > condition stmt to the preheader instead of iters_bb.
>
gcc_test.c
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