* [PATCH] tree-optimization/101280 - revise interchange fix for PR101173
@ 2021-07-01 11:38 Richard Biener
2021-07-01 14:49 ` Michael Matz
0 siblings, 1 reply; 4+ messages in thread
From: Richard Biener @ 2021-07-01 11:38 UTC (permalink / raw)
To: gcc-patches; +Cc: bin.cheng
The following revises the original fix for PR101173 to correctly
check for a reversed dependence rather than disallowing a zero
distance. It also adds a check from TSVC which asks for this
kind of interchange (but with a valid dependence).
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2021-07-01 Richard Biener <rguenther@suse.de>
PR tree-optimization/101280
PR tree-optimization/101173
* gimple-loop-interchange.cc
(tree_loop_interchange::valid_data_dependences): Revert
previous change and instead correctly handle DDR_REVERSED_P
dependence.
* gcc.dg/tree-ssa/loop-interchange-16.c: New testcase.
---
gcc/gimple-loop-interchange.cc | 7 ++++--
.../gcc.dg/tree-ssa/loop-interchange-16.c | 22 +++++++++++++++++++
2 files changed, 27 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/loop-interchange-16.c
diff --git a/gcc/gimple-loop-interchange.cc b/gcc/gimple-loop-interchange.cc
index 43045c5455e..43ef112a2d0 100644
--- a/gcc/gimple-loop-interchange.cc
+++ b/gcc/gimple-loop-interchange.cc
@@ -1043,8 +1043,11 @@ tree_loop_interchange::valid_data_dependences (unsigned i_idx, unsigned o_idx,
continue;
/* Be conservative, skip case if either direction at i_idx/o_idx
- levels is not '=' (for the inner loop) or '<'. */
- if (dist_vect[i_idx] < 0 || dist_vect[o_idx] <= 0)
+ levels is not '=' or '<'. */
+ if (dist_vect[i_idx] < 0
+ || (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
+ || dist_vect[o_idx] < 0
+ || (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
return false;
}
}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/loop-interchange-16.c b/gcc/testsuite/gcc.dg/tree-ssa/loop-interchange-16.c
new file mode 100644
index 00000000000..781555e085d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/loop-interchange-16.c
@@ -0,0 +1,22 @@
+/* PR/101280 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-tree-linterchange-details" } */
+
+void dummy (double *, double *);
+#define LEN_2D 32
+double aa[LEN_2D][LEN_2D], bb[LEN_2D][LEN_2D];
+double s231(int iterations)
+{
+// loop interchange
+// loop with data dependency
+ for (int nl = 0; nl < 100*(iterations/LEN_2D); nl++) {
+ for (int i = 0; i < LEN_2D; ++i) {
+ for (int j = 1; j < LEN_2D; j++) {
+ aa[j][i] = aa[j - 1][i] + bb[j][i];
+ }
+ }
+ dummy(aa[0],bb[0]);
+ }
+}
+
+/* { dg-final { scan-tree-dump "loops interchanged" "linterchange" } } */
--
2.26.2
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tree-optimization/101280 - revise interchange fix for PR101173
2021-07-01 11:38 [PATCH] tree-optimization/101280 - revise interchange fix for PR101173 Richard Biener
@ 2021-07-01 14:49 ` Michael Matz
2021-07-02 6:03 ` Richard Biener
0 siblings, 1 reply; 4+ messages in thread
From: Michael Matz @ 2021-07-01 14:49 UTC (permalink / raw)
To: Richard Biener; +Cc: gcc-patches, bin.cheng
Hello,
On Thu, 1 Jul 2021, Richard Biener wrote:
> diff --git a/gcc/gimple-loop-interchange.cc b/gcc/gimple-loop-interchange.cc
> index 43045c5455e..43ef112a2d0 100644
> --- a/gcc/gimple-loop-interchange.cc
> +++ b/gcc/gimple-loop-interchange.cc
> @@ -1043,8 +1043,11 @@ tree_loop_interchange::valid_data_dependences (unsigned i_idx, unsigned o_idx,
> continue;
>
> /* Be conservative, skip case if either direction at i_idx/o_idx
> - levels is not '=' (for the inner loop) or '<'. */
> - if (dist_vect[i_idx] < 0 || dist_vect[o_idx] <= 0)
> + levels is not '=' or '<'. */
> + if (dist_vect[i_idx] < 0
> + || (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
> + || dist_vect[o_idx] < 0
> + || (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
Hmm, if DDR_REVERSED_P matters here, then it should matter for all arms.
IOW: < 0 should be tested only when !DDR_REVERSED_P, not always:
if ((!DDR_REVERSED_P (ddr) && dist_vect[i_idx] < 0)
|| (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
|| (!DDR_REVERSED_P (ddr) && dist_vect[o_idx] < 0)
|| (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
(what you have effectively written is a condition that allows only 0 when
DDR_REVERSED_P)
Ciao,
Michael.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tree-optimization/101280 - revise interchange fix for PR101173
2021-07-01 14:49 ` Michael Matz
@ 2021-07-02 6:03 ` Richard Biener
2021-07-02 6:54 ` Richard Biener
0 siblings, 1 reply; 4+ messages in thread
From: Richard Biener @ 2021-07-02 6:03 UTC (permalink / raw)
To: Michael Matz; +Cc: gcc-patches, bin.cheng
On Thu, 1 Jul 2021, Michael Matz wrote:
> Hello,
>
> On Thu, 1 Jul 2021, Richard Biener wrote:
>
> > diff --git a/gcc/gimple-loop-interchange.cc b/gcc/gimple-loop-interchange.cc
> > index 43045c5455e..43ef112a2d0 100644
> > --- a/gcc/gimple-loop-interchange.cc
> > +++ b/gcc/gimple-loop-interchange.cc
> > @@ -1043,8 +1043,11 @@ tree_loop_interchange::valid_data_dependences (unsigned i_idx, unsigned o_idx,
> > continue;
> >
> > /* Be conservative, skip case if either direction at i_idx/o_idx
> > - levels is not '=' (for the inner loop) or '<'. */
> > - if (dist_vect[i_idx] < 0 || dist_vect[o_idx] <= 0)
> > + levels is not '=' or '<'. */
> > + if (dist_vect[i_idx] < 0
> > + || (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
> > + || dist_vect[o_idx] < 0
> > + || (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
>
> Hmm, if DDR_REVERSED_P matters here, then it should matter for all arms.
> IOW: < 0 should be tested only when !DDR_REVERSED_P, not always:
>
> if ((!DDR_REVERSED_P (ddr) && dist_vect[i_idx] < 0)
> || (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
> || (!DDR_REVERSED_P (ddr) && dist_vect[o_idx] < 0)
> || (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
>
> (what you have effectively written is a condition that allows only 0 when
> DDR_REVERSED_P)
True - been fixing bugs too fast I guess. Maybe the 3rd time's the charm
then ;)
Richard.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tree-optimization/101280 - revise interchange fix for PR101173
2021-07-02 6:03 ` Richard Biener
@ 2021-07-02 6:54 ` Richard Biener
0 siblings, 0 replies; 4+ messages in thread
From: Richard Biener @ 2021-07-02 6:54 UTC (permalink / raw)
To: Michael Matz; +Cc: gcc-patches, bin.cheng
On Fri, 2 Jul 2021, Richard Biener wrote:
> On Thu, 1 Jul 2021, Michael Matz wrote:
>
> > Hello,
> >
> > On Thu, 1 Jul 2021, Richard Biener wrote:
> >
> > > diff --git a/gcc/gimple-loop-interchange.cc b/gcc/gimple-loop-interchange.cc
> > > index 43045c5455e..43ef112a2d0 100644
> > > --- a/gcc/gimple-loop-interchange.cc
> > > +++ b/gcc/gimple-loop-interchange.cc
> > > @@ -1043,8 +1043,11 @@ tree_loop_interchange::valid_data_dependences (unsigned i_idx, unsigned o_idx,
> > > continue;
> > >
> > > /* Be conservative, skip case if either direction at i_idx/o_idx
> > > - levels is not '=' (for the inner loop) or '<'. */
> > > - if (dist_vect[i_idx] < 0 || dist_vect[o_idx] <= 0)
> > > + levels is not '=' or '<'. */
> > > + if (dist_vect[i_idx] < 0
> > > + || (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
> > > + || dist_vect[o_idx] < 0
> > > + || (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
> >
> > Hmm, if DDR_REVERSED_P matters here, then it should matter for all arms.
> > IOW: < 0 should be tested only when !DDR_REVERSED_P, not always:
> >
> > if ((!DDR_REVERSED_P (ddr) && dist_vect[i_idx] < 0)
> > || (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
> > || (!DDR_REVERSED_P (ddr) && dist_vect[o_idx] < 0)
> > || (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
> >
> > (what you have effectively written is a condition that allows only 0 when
> > DDR_REVERSED_P)
>
> True - been fixing bugs too fast I guess. Maybe the 3rd time's the charm
> then ;)
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
Richard.
From 094af28137de5c55a21123c3b4e06e7d7a08bb5a Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Fri, 2 Jul 2021 08:51:43 +0200
Subject: [PATCH] tree-optimization/101280 - re-revise interchange fix for
PR101173
To: gcc-patches@gcc.gnu.org
The following fixes up the revision of the original fix for PR101173
to properly guard all dependence checks with DDR_REVERSED_P or its
inverse.
2021-07-01 Richard Biener <rguenther@suse.de>
PR tree-optimization/101280
PR tree-optimization/101173
* gimple-loop-interchange.cc
(tree_loop_interchange::valid_data_dependences): Properly
guard all dependence checks with DDR_REVERSED_P or its
inverse.
---
gcc/gimple-loop-interchange.cc | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/gimple-loop-interchange.cc b/gcc/gimple-loop-interchange.cc
index 43ef112a2d0..7a88faa2c07 100644
--- a/gcc/gimple-loop-interchange.cc
+++ b/gcc/gimple-loop-interchange.cc
@@ -1044,9 +1044,9 @@ tree_loop_interchange::valid_data_dependences (unsigned i_idx, unsigned o_idx,
/* Be conservative, skip case if either direction at i_idx/o_idx
levels is not '=' or '<'. */
- if (dist_vect[i_idx] < 0
+ if ((!DDR_REVERSED_P (ddr) && dist_vect[i_idx] < 0)
|| (DDR_REVERSED_P (ddr) && dist_vect[i_idx] > 0)
- || dist_vect[o_idx] < 0
+ || (!DDR_REVERSED_P (ddr) && dist_vect[o_idx] < 0)
|| (DDR_REVERSED_P (ddr) && dist_vect[o_idx] > 0))
return false;
}
--
2.26.2
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