| Message ID | ZUiYgMOPSBbV8F+/@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
Ping > -----Original Message----- > From: Tamar Christina <tamar.christina@arm.com> > Sent: Monday, November 6, 2023 7:41 AM > To: gcc-patches@gcc.gnu.org > Cc: nd <nd@arm.com>; rguenther@suse.de; jlaw@ventanamicro.com > Subject: [PATCH 13/21]middle-end: Update loop form analysis to support > early break > > Hi All, > > This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the > other patches are self contained. > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > Ok for master? > > Thanks, > Tamar > > gcc/ChangeLog: > > * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. > (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. > (vect_transform_loop): Use it. > > --- inline copy of patch -- > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index > 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb > 991f07cd6052491d0 100644 > --- a/gcc/tree-vect-loop.cc > +++ b/gcc/tree-vect-loop.cc > @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost > (loop_vec_info loop_vinfo) > loop_vinfo->scalar_costs->finish_cost (nullptr); } > > - > /* Function vect_analyze_loop_form. > > Verify that certain CFG restrictions hold, including: > - the loop has a pre-header > - - the loop has a single entry and exit > + - the loop has a single entry > + - nested loops can have only a single exit. > - the loop exit condition is simple enough > - the number of iterations can be analyzed, i.e, a countable loop. The > niter could be analyzed under some assumptions. */ @@ -1841,10 > +1841,14 @@ vect_analyze_loop_form (class loop *loop, > vect_loop_form_info *info) > "not vectorized: latch block not empty.\n"); > > /* Make sure the exit is not abnormal. */ > - if (exit_e->flags & EDGE_ABNORMAL) > - return opt_result::failure_at (vect_location, > - "not vectorized:" > - " abnormal loop exit edge.\n"); > + auto_vec<edge> exits = get_loop_exit_edges (loop); > + for (edge e : exits) > + { > + if (e->flags & EDGE_ABNORMAL) > + return opt_result::failure_at (vect_location, > + "not vectorized:" > + " abnormal loop exit edge.\n"); > + } > > info->conds > = vect_get_loop_niters (loop, exit_e, &info->assumptions, @@ -1920,6 > +1924,10 @@ vect_create_loop_vinfo (class loop *loop, vec_info_shared > *shared, > > LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; > > + /* Check to see if we're vectorizing multiple exits. */ > + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) > + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); > + > if (info->inner_loop_cond) > { > stmt_vec_info inner_loop_cond_info @@ -11577,7 +11585,7 @@ > vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call) > /* Make sure there exists a single-predecessor exit bb. Do this before > versioning. */ > edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); > - if (! single_pred_p (e->dest)) > + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS > + (loop_vinfo)) > { > split_loop_exit_edge (e, true); > if (dump_enabled_p ()) > > > > > --
ping > -----Original Message----- > From: Tamar Christina <Tamar.Christina@arm.com> > Sent: Monday, November 27, 2023 10:48 PM > To: Tamar Christina <Tamar.Christina@arm.com>; gcc-patches@gcc.gnu.org > Cc: nd <nd@arm.com>; rguenther@suse.de; jlaw@ventanamicro.com > Subject: RE: [PATCH 13/21]middle-end: Update loop form analysis to support early > break > > Ping > > > -----Original Message----- > > From: Tamar Christina <tamar.christina@arm.com> > > Sent: Monday, November 6, 2023 7:41 AM > > To: gcc-patches@gcc.gnu.org > > Cc: nd <nd@arm.com>; rguenther@suse.de; jlaw@ventanamicro.com > > Subject: [PATCH 13/21]middle-end: Update loop form analysis to support > > early break > > > > Hi All, > > > > This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the > > other patches are self contained. > > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > > > Ok for master? > > > > Thanks, > > Tamar > > > > gcc/ChangeLog: > > > > * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. > > (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. > > (vect_transform_loop): Use it. > > > > --- inline copy of patch -- > > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index > > 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb > > 991f07cd6052491d0 100644 > > --- a/gcc/tree-vect-loop.cc > > +++ b/gcc/tree-vect-loop.cc > > @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost > > (loop_vec_info loop_vinfo) > > loop_vinfo->scalar_costs->finish_cost (nullptr); } > > > > - > > /* Function vect_analyze_loop_form. > > > > Verify that certain CFG restrictions hold, including: > > - the loop has a pre-header > > - - the loop has a single entry and exit > > + - the loop has a single entry > > + - nested loops can have only a single exit. > > - the loop exit condition is simple enough > > - the number of iterations can be analyzed, i.e, a countable loop. The > > niter could be analyzed under some assumptions. */ @@ -1841,10 > > +1841,14 @@ vect_analyze_loop_form (class loop *loop, > > vect_loop_form_info *info) > > "not vectorized: latch block not empty.\n"); > > > > /* Make sure the exit is not abnormal. */ > > - if (exit_e->flags & EDGE_ABNORMAL) > > - return opt_result::failure_at (vect_location, > > - "not vectorized:" > > - " abnormal loop exit edge.\n"); > > + auto_vec<edge> exits = get_loop_exit_edges (loop); > > + for (edge e : exits) > > + { > > + if (e->flags & EDGE_ABNORMAL) > > + return opt_result::failure_at (vect_location, > > + "not vectorized:" > > + " abnormal loop exit edge.\n"); > > + } > > > > info->conds > > = vect_get_loop_niters (loop, exit_e, &info->assumptions, @@ -1920,6 > > +1924,10 @@ vect_create_loop_vinfo (class loop *loop, vec_info_shared > > *shared, > > > > LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; > > > > + /* Check to see if we're vectorizing multiple exits. */ > > + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) > > + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); > > + > > if (info->inner_loop_cond) > > { > > stmt_vec_info inner_loop_cond_info @@ -11577,7 +11585,7 @@ > > vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call) > > /* Make sure there exists a single-predecessor exit bb. Do this before > > versioning. */ > > edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); > > - if (! single_pred_p (e->dest)) > > + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS > > + (loop_vinfo)) > > { > > split_loop_exit_edge (e, true); > > if (dump_enabled_p ()) > > > > > > > > > > --
On Mon, 6 Nov 2023, Tamar Christina wrote: > Hi All, > > This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the other > patches are self contained. > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > Ok for master? > > Thanks, > Tamar > > gcc/ChangeLog: > > * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. > (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. > (vect_transform_loop): Use it. > > --- inline copy of patch -- > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > index 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb991f07cd6052491d0 100644 > --- a/gcc/tree-vect-loop.cc > +++ b/gcc/tree-vect-loop.cc > @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost (loop_vec_info loop_vinfo) > loop_vinfo->scalar_costs->finish_cost (nullptr); > } > > - > /* Function vect_analyze_loop_form. > > Verify that certain CFG restrictions hold, including: > - the loop has a pre-header > - - the loop has a single entry and exit > + - the loop has a single entry > + - nested loops can have only a single exit. > - the loop exit condition is simple enough > - the number of iterations can be analyzed, i.e, a countable loop. The > niter could be analyzed under some assumptions. */ > @@ -1841,10 +1841,14 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info) > "not vectorized: latch block not empty.\n"); > > /* Make sure the exit is not abnormal. */ > - if (exit_e->flags & EDGE_ABNORMAL) > - return opt_result::failure_at (vect_location, > - "not vectorized:" > - " abnormal loop exit edge.\n"); > + auto_vec<edge> exits = get_loop_exit_edges (loop); > + for (edge e : exits) Seeing this multiple times, this isn't the most efficient way to iterate over all exits with LOOPS_HAVE_RECORDED_EXITS. Note to myself: fix (add to) the API. > + { > + if (e->flags & EDGE_ABNORMAL) > + return opt_result::failure_at (vect_location, > + "not vectorized:" > + " abnormal loop exit edge.\n"); > + } > > info->conds > = vect_get_loop_niters (loop, exit_e, &info->assumptions, > @@ -1920,6 +1924,10 @@ vect_create_loop_vinfo (class loop *loop, vec_info_shared *shared, > > LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; > > + /* Check to see if we're vectorizing multiple exits. */ > + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) > + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); > + Seeing this, s/LOOP_VINFO_LOOP_CONDS/LOOP_VINFO_LOOP_EXIT_CONDS/g might be good, if we in future avoid if-conversion in a separate pass we will have other CONDs as well. > if (info->inner_loop_cond) > { > stmt_vec_info inner_loop_cond_info > @@ -11577,7 +11585,7 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call) > /* Make sure there exists a single-predecessor exit bb. Do this before > versioning. */ > edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); > - if (! single_pred_p (e->dest)) > + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS (loop_vinfo)) > { > split_loop_exit_edge (e, true); Note this splitting is done to fulfil versioning constraints on CFG update. Do you have test coverage with alias versioning and early breaks? Otherwise OK. Thanks, Richard.
> -----Original Message----- > From: Richard Biener <rguenther@suse.de> > Sent: Wednesday, December 6, 2023 8:18 AM > To: Tamar Christina <Tamar.Christina@arm.com> > Cc: gcc-patches@gcc.gnu.org; nd <nd@arm.com>; jlaw@ventanamicro.com > Subject: Re: [PATCH 13/21]middle-end: Update loop form analysis to support early > break > > On Mon, 6 Nov 2023, Tamar Christina wrote: > > > Hi All, > > > > This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the other > > patches are self contained. > > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > > > Ok for master? > > > > Thanks, > > Tamar > > > > gcc/ChangeLog: > > > > * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. > > (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. > > (vect_transform_loop): Use it. > > > > --- inline copy of patch -- > > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > > index > 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb991 > f07cd6052491d0 100644 > > --- a/gcc/tree-vect-loop.cc > > +++ b/gcc/tree-vect-loop.cc > > @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost > (loop_vec_info loop_vinfo) > > loop_vinfo->scalar_costs->finish_cost (nullptr); > > } > > > > - > > /* Function vect_analyze_loop_form. > > > > Verify that certain CFG restrictions hold, including: > > - the loop has a pre-header > > - - the loop has a single entry and exit > > + - the loop has a single entry > > + - nested loops can have only a single exit. > > - the loop exit condition is simple enough > > - the number of iterations can be analyzed, i.e, a countable loop. The > > niter could be analyzed under some assumptions. */ > > @@ -1841,10 +1841,14 @@ vect_analyze_loop_form (class loop *loop, > vect_loop_form_info *info) > > "not vectorized: latch block not empty.\n"); > > > > /* Make sure the exit is not abnormal. */ > > - if (exit_e->flags & EDGE_ABNORMAL) > > - return opt_result::failure_at (vect_location, > > - "not vectorized:" > > - " abnormal loop exit edge.\n"); > > + auto_vec<edge> exits = get_loop_exit_edges (loop); > > + for (edge e : exits) > > Seeing this multiple times, this isn't the most efficient way to > iterate over all exits with LOOPS_HAVE_RECORDED_EXITS. > > Note to myself: fix (add to) the API. > > > + { > > + if (e->flags & EDGE_ABNORMAL) > > + return opt_result::failure_at (vect_location, > > + "not vectorized:" > > + " abnormal loop exit edge.\n"); > > + } > > > > info->conds > > = vect_get_loop_niters (loop, exit_e, &info->assumptions, > > @@ -1920,6 +1924,10 @@ vect_create_loop_vinfo (class loop *loop, > vec_info_shared *shared, > > > > LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; > > > > + /* Check to see if we're vectorizing multiple exits. */ > > + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) > > + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); > > + > > Seeing this, s/LOOP_VINFO_LOOP_CONDS/LOOP_VINFO_LOOP_EXIT_CONDS/g > might be good, if we in future avoid if-conversion in a separate > pass we will have other CONDs as well. > > > if (info->inner_loop_cond) > > { > > stmt_vec_info inner_loop_cond_info > > @@ -11577,7 +11585,7 @@ vect_transform_loop (loop_vec_info loop_vinfo, > gimple *loop_vectorized_call) > > /* Make sure there exists a single-predecessor exit bb. Do this before > > versioning. */ > > edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); > > - if (! single_pred_p (e->dest)) > > + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS (loop_vinfo)) > > { > > split_loop_exit_edge (e, true); > > Note this splitting is done to fulfil versioning constraints on CFG > update. Do you have test coverage with alias versioning and early > breaks? No, only non-alias versioning. I don't believe we can alias in the current implementation because it's restricted to statically known objects with a fixed size. Thanks, Tamar > > Otherwise OK. > > Thanks, > Richard.
On Wed, 6 Dec 2023, Tamar Christina wrote: > > -----Original Message----- > > From: Richard Biener <rguenther@suse.de> > > Sent: Wednesday, December 6, 2023 8:18 AM > > To: Tamar Christina <Tamar.Christina@arm.com> > > Cc: gcc-patches@gcc.gnu.org; nd <nd@arm.com>; jlaw@ventanamicro.com > > Subject: Re: [PATCH 13/21]middle-end: Update loop form analysis to support early > > break > > > > On Mon, 6 Nov 2023, Tamar Christina wrote: > > > > > Hi All, > > > > > > This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the other > > > patches are self contained. > > > > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > > > > > Ok for master? > > > > > > Thanks, > > > Tamar > > > > > > gcc/ChangeLog: > > > > > > * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. > > > (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. > > > (vect_transform_loop): Use it. > > > > > > --- inline copy of patch -- > > > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > > > index > > 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb991 > > f07cd6052491d0 100644 > > > --- a/gcc/tree-vect-loop.cc > > > +++ b/gcc/tree-vect-loop.cc > > > @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost > > (loop_vec_info loop_vinfo) > > > loop_vinfo->scalar_costs->finish_cost (nullptr); > > > } > > > > > > - > > > /* Function vect_analyze_loop_form. > > > > > > Verify that certain CFG restrictions hold, including: > > > - the loop has a pre-header > > > - - the loop has a single entry and exit > > > + - the loop has a single entry > > > + - nested loops can have only a single exit. > > > - the loop exit condition is simple enough > > > - the number of iterations can be analyzed, i.e, a countable loop. The > > > niter could be analyzed under some assumptions. */ > > > @@ -1841,10 +1841,14 @@ vect_analyze_loop_form (class loop *loop, > > vect_loop_form_info *info) > > > "not vectorized: latch block not empty.\n"); > > > > > > /* Make sure the exit is not abnormal. */ > > > - if (exit_e->flags & EDGE_ABNORMAL) > > > - return opt_result::failure_at (vect_location, > > > - "not vectorized:" > > > - " abnormal loop exit edge.\n"); > > > + auto_vec<edge> exits = get_loop_exit_edges (loop); > > > + for (edge e : exits) > > > > Seeing this multiple times, this isn't the most efficient way to > > iterate over all exits with LOOPS_HAVE_RECORDED_EXITS. > > > > Note to myself: fix (add to) the API. > > > > > + { > > > + if (e->flags & EDGE_ABNORMAL) > > > + return opt_result::failure_at (vect_location, > > > + "not vectorized:" > > > + " abnormal loop exit edge.\n"); > > > + } > > > > > > info->conds > > > = vect_get_loop_niters (loop, exit_e, &info->assumptions, > > > @@ -1920,6 +1924,10 @@ vect_create_loop_vinfo (class loop *loop, > > vec_info_shared *shared, > > > > > > LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; > > > > > > + /* Check to see if we're vectorizing multiple exits. */ > > > + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) > > > + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); > > > + > > > > Seeing this, s/LOOP_VINFO_LOOP_CONDS/LOOP_VINFO_LOOP_EXIT_CONDS/g > > might be good, if we in future avoid if-conversion in a separate > > pass we will have other CONDs as well. > > > > > if (info->inner_loop_cond) > > > { > > > stmt_vec_info inner_loop_cond_info > > > @@ -11577,7 +11585,7 @@ vect_transform_loop (loop_vec_info loop_vinfo, > > gimple *loop_vectorized_call) > > > /* Make sure there exists a single-predecessor exit bb. Do this before > > > versioning. */ > > > edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); > > > - if (! single_pred_p (e->dest)) > > > + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS (loop_vinfo)) > > > { > > > split_loop_exit_edge (e, true); > > > > Note this splitting is done to fulfil versioning constraints on CFG > > update. Do you have test coverage with alias versioning and early > > breaks? > > No, only non-alias versioning. I don't believe we can alias in the current > implementation because it's restricted to statically known objects with > a fixed size. Hm, if side-effects are all correctly in place do we still have that restriction? int x; void foo (int *a, int *b) { int local_x = x; for (int i = 0; i < 1024; ++i) { if (i % local_x == 13) break; a[i] = 2 * b[i]; } } the early exit isn't SCEV analyzable but doesn't depend on any memory and all side-effects are after the exit already. But vectorizing would require alias versioning. Richard.
> -----Original Message----- > From: Richard Biener <rguenther@suse.de> > Sent: Wednesday, December 6, 2023 9:15 AM > To: Tamar Christina <Tamar.Christina@arm.com> > Cc: gcc-patches@gcc.gnu.org; nd <nd@arm.com>; jlaw@ventanamicro.com > Subject: RE: [PATCH 13/21]middle-end: Update loop form analysis to support early > break > > On Wed, 6 Dec 2023, Tamar Christina wrote: > > > > -----Original Message----- > > > From: Richard Biener <rguenther@suse.de> > > > Sent: Wednesday, December 6, 2023 8:18 AM > > > To: Tamar Christina <Tamar.Christina@arm.com> > > > Cc: gcc-patches@gcc.gnu.org; nd <nd@arm.com>; jlaw@ventanamicro.com > > > Subject: Re: [PATCH 13/21]middle-end: Update loop form analysis to support > early > > > break > > > > > > On Mon, 6 Nov 2023, Tamar Christina wrote: > > > > > > > Hi All, > > > > > > > > This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the > other > > > > patches are self contained. > > > > > > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > > > > > > > Ok for master? > > > > > > > > Thanks, > > > > Tamar > > > > > > > > gcc/ChangeLog: > > > > > > > > * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. > > > > (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. > > > > (vect_transform_loop): Use it. > > > > > > > > --- inline copy of patch -- > > > > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > > > > index > > > > 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb991 > > > f07cd6052491d0 100644 > > > > --- a/gcc/tree-vect-loop.cc > > > > +++ b/gcc/tree-vect-loop.cc > > > > @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost > > > (loop_vec_info loop_vinfo) > > > > loop_vinfo->scalar_costs->finish_cost (nullptr); > > > > } > > > > > > > > - > > > > /* Function vect_analyze_loop_form. > > > > > > > > Verify that certain CFG restrictions hold, including: > > > > - the loop has a pre-header > > > > - - the loop has a single entry and exit > > > > + - the loop has a single entry > > > > + - nested loops can have only a single exit. > > > > - the loop exit condition is simple enough > > > > - the number of iterations can be analyzed, i.e, a countable loop. The > > > > niter could be analyzed under some assumptions. */ > > > > @@ -1841,10 +1841,14 @@ vect_analyze_loop_form (class loop *loop, > > > vect_loop_form_info *info) > > > > "not vectorized: latch block not empty.\n"); > > > > > > > > /* Make sure the exit is not abnormal. */ > > > > - if (exit_e->flags & EDGE_ABNORMAL) > > > > - return opt_result::failure_at (vect_location, > > > > - "not vectorized:" > > > > - " abnormal loop exit edge.\n"); > > > > + auto_vec<edge> exits = get_loop_exit_edges (loop); > > > > + for (edge e : exits) > > > > > > Seeing this multiple times, this isn't the most efficient way to > > > iterate over all exits with LOOPS_HAVE_RECORDED_EXITS. > > > > > > Note to myself: fix (add to) the API. > > > > > > > + { > > > > + if (e->flags & EDGE_ABNORMAL) > > > > + return opt_result::failure_at (vect_location, > > > > + "not vectorized:" > > > > + " abnormal loop exit edge.\n"); > > > > + } > > > > > > > > info->conds > > > > = vect_get_loop_niters (loop, exit_e, &info->assumptions, > > > > @@ -1920,6 +1924,10 @@ vect_create_loop_vinfo (class loop *loop, > > > vec_info_shared *shared, > > > > > > > > LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; > > > > > > > > + /* Check to see if we're vectorizing multiple exits. */ > > > > + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) > > > > + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); > > > > + > > > > > > Seeing this, > s/LOOP_VINFO_LOOP_CONDS/LOOP_VINFO_LOOP_EXIT_CONDS/g > > > might be good, if we in future avoid if-conversion in a separate > > > pass we will have other CONDs as well. > > > > > > > if (info->inner_loop_cond) > > > > { > > > > stmt_vec_info inner_loop_cond_info > > > > @@ -11577,7 +11585,7 @@ vect_transform_loop (loop_vec_info > loop_vinfo, > > > gimple *loop_vectorized_call) > > > > /* Make sure there exists a single-predecessor exit bb. Do this before > > > > versioning. */ > > > > edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); > > > > - if (! single_pred_p (e->dest)) > > > > + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS > (loop_vinfo)) > > > > { > > > > split_loop_exit_edge (e, true); > > > > > > Note this splitting is done to fulfil versioning constraints on CFG > > > update. Do you have test coverage with alias versioning and early > > > breaks? > > > > No, only non-alias versioning. I don't believe we can alias in the current > > implementation because it's restricted to statically known objects with > > a fixed size. > > Hm, if side-effects are all correctly in place do we still have that > restriction? > > int x; > void foo (int *a, int *b) > { > int local_x = x; > for (int i = 0; i < 1024; ++i) > { > if (i % local_x == 13) > break; > a[i] = 2 * b[i]; > } > } > > the early exit isn't SCEV analyzable but doesn't depend on any > memory and all side-effects are after the exit already. But > vectorizing would require alias versioning. Oh, you're right. A slightly simpler testcase: int x; void foo (int *a, int *b) { int local_x = x; for (int i = 0; i < 1024; ++i) { if (i + local_x == 13) break; a[i] = 2 * b[i]; } } Vectorizes and has added the correct alias check. uwl-alias.c:9:19: missed: versioning for alias required: can't determine dependence between *_4 and *_6 consider run-time aliasing test between *_4 and *_6 merged alias checks: reference: *_4 vs. *_6 segment length: 12 access size: 4 alignment: 4 flags: WAR uwl-alias.c:5:21: note: improved number of alias checks from 1 to 1 uwl-alias.c:5:21: note: created 1 versioning for alias checks. uwl-alias.c:5:21: note: trying to apply versioning to outer loop 0 So I'll make it a runtime test and added it to the testsuite. Cheers, Tamar > > Richard.
--- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost (loop_vec_info loop_vinfo) loop_vinfo->scalar_costs->finish_cost (nullptr); } - /* Function vect_analyze_loop_form. Verify that certain CFG restrictions hold, including: - the loop has a pre-header - - the loop has a single entry and exit + - the loop has a single entry + - nested loops can have only a single exit. - the loop exit condition is simple enough - the number of iterations can be analyzed, i.e, a countable loop. The niter could be analyzed under some assumptions. */ @@ -1841,10 +1841,14 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info) "not vectorized: latch block not empty.\n"); /* Make sure the exit is not abnormal. */ - if (exit_e->flags & EDGE_ABNORMAL) - return opt_result::failure_at (vect_location, - "not vectorized:" - " abnormal loop exit edge.\n"); + auto_vec<edge> exits = get_loop_exit_edges (loop); + for (edge e : exits) + { + if (e->flags & EDGE_ABNORMAL) + return opt_result::failure_at (vect_location, + "not vectorized:" + " abnormal loop exit edge.\n"); + } info->conds = vect_get_loop_niters (loop, exit_e, &info->assumptions, @@ -1920,6 +1924,10 @@ vect_create_loop_vinfo (class loop *loop, vec_info_shared *shared, LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; + /* Check to see if we're vectorizing multiple exits. */ + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); + if (info->inner_loop_cond) { stmt_vec_info inner_loop_cond_info @@ -11577,7 +11585,7 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call) /* Make sure there exists a single-predecessor exit bb. Do this before versioning. */ edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); - if (! single_pred_p (e->dest)) + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS (loop_vinfo)) { split_loop_exit_edge (e, true); if (dump_enabled_p ())
Hi All, This sets LOOP_VINFO_EARLY_BREAKS and does some misc changes so the other patches are self contained. Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. Ok for master? Thanks, Tamar gcc/ChangeLog: * tree-vect-loop.cc (vect_analyze_loop_form): Analyse all exits. (vect_create_loop_vinfo): Set LOOP_VINFO_EARLY_BREAKS. (vect_transform_loop): Use it. --- inline copy of patch -- diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb991f07cd6052491d0 100644 -- diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index 51a054c5b035ac80dfbbf3b5ba2f6da82fda91f6..f9483eff6e9606e835906fb991f07cd6052491d0 100644 --- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -1700,12 +1700,12 @@ vect_compute_single_scalar_iteration_cost (loop_vec_info loop_vinfo) loop_vinfo->scalar_costs->finish_cost (nullptr); } - /* Function vect_analyze_loop_form. Verify that certain CFG restrictions hold, including: - the loop has a pre-header - - the loop has a single entry and exit + - the loop has a single entry + - nested loops can have only a single exit. - the loop exit condition is simple enough - the number of iterations can be analyzed, i.e, a countable loop. The niter could be analyzed under some assumptions. */ @@ -1841,10 +1841,14 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info) "not vectorized: latch block not empty.\n"); /* Make sure the exit is not abnormal. */ - if (exit_e->flags & EDGE_ABNORMAL) - return opt_result::failure_at (vect_location, - "not vectorized:" - " abnormal loop exit edge.\n"); + auto_vec<edge> exits = get_loop_exit_edges (loop); + for (edge e : exits) + { + if (e->flags & EDGE_ABNORMAL) + return opt_result::failure_at (vect_location, + "not vectorized:" + " abnormal loop exit edge.\n"); + } info->conds = vect_get_loop_niters (loop, exit_e, &info->assumptions, @@ -1920,6 +1924,10 @@ vect_create_loop_vinfo (class loop *loop, vec_info_shared *shared, LOOP_VINFO_IV_EXIT (loop_vinfo) = info->loop_exit; + /* Check to see if we're vectorizing multiple exits. */ + LOOP_VINFO_EARLY_BREAKS (loop_vinfo) + = !LOOP_VINFO_LOOP_CONDS (loop_vinfo).is_empty (); + if (info->inner_loop_cond) { stmt_vec_info inner_loop_cond_info @@ -11577,7 +11585,7 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call) /* Make sure there exists a single-predecessor exit bb. Do this before versioning. */ edge e = LOOP_VINFO_IV_EXIT (loop_vinfo); - if (! single_pred_p (e->dest)) + if (! single_pred_p (e->dest) && !LOOP_VINFO_EARLY_BREAKS (loop_vinfo)) { split_loop_exit_edge (e, true); if (dump_enabled_p ())