Re: [PATCH] Fix PR81038

[Richard Biener <richard dot guenther at gmail dot com>]

On Sat, Feb 3, 2018 at 12:30 AM, Bill Schmidt
<wschmidt@linux.vnet.ibm.com> wrote:
> Hi,
>
> The test g++.dg/vect/slp-pr56812.cc is somewhat fragile and is currently failing
> on several targets.  PR81038 notes that this began with r248678, which stopped
> some inferior peeling solutions from preventing vectorization that could be done
> without peeling.  I observed that for powerpc64le, r248677 vectorizes the code
> during SLP, but r248678 vectorizes it during the loop vectorization pass.  Which
> pass does the vectorization is quite dependent on cost model, which for us is a
> quite close decision.  In any case, the important thing is that the code is
> vectorized, not which pass does it.
>
> This patch prevents the test from flipping in and out of failure status depending
> on which pass does the vectorization, by testing the final "optimized" dump for
> the expected vectorized output instead of relying on a specific vectorization
> pass dump.
>
> By the way, the test case somehow had gotten DOS/Windows newlines into it, so
> I removed those.  The ^M characters disappeared when I pasted into this mailer,
> unfortunately.  Anyway, that's the reason for the full replacement of the file.
> The only real changes are the dg-final directives and the documentation of the
> expected output.
>
> Verified on powerpc64le-unknown-linux-gnu.  Is this okay for trunk?

Hmm.  That removes the existing XFAIL.  Also wouldn't it be more elegant to do
the following?  This makes the testcase pass on x86_64, thus committed ;)

Richard.

2018-02-08  Richard Biener  <rguenther@suse.de>

        * g++.dg/vect/slp-pr56812.cc: Allow either basic-block or
        loop vectorization to happen.

Index: gcc/testsuite/g++.dg/vect/slp-pr56812.cc
===================================================================
--- gcc/testsuite/g++.dg/vect/slp-pr56812.cc    (revision 257477)
+++ gcc/testsuite/g++.dg/vect/slp-pr56812.cc    (working copy)
@@ -1,7 +1,7 @@
 /* { dg-do compile } */
 /* { dg-require-effective-target vect_float } */
 /* { dg-require-effective-target vect_hw_misalign } */
-/* { dg-additional-options "-O3 -funroll-loops -fvect-cost-model=dynamic" } */
+/* { dg-additional-options "-O3 -funroll-loops
-fvect-cost-model=dynamic -fopt-info-vec" } */

 class mydata {
 public:
@@ -13,10 +13,7 @@ public:

 void mydata::Set (float x)
 {
-  for (int i=0; i<upper(); i++)
+  /* We want to vectorize this either as loop or basic-block.  */
+  for (int i=0; i<upper(); i++) /* { dg-message "note: \[^\n\]*
vectorized" } */
     data[i] = x;
 }
-
-/* For targets without vector loop peeling the loop becomes cheap
-   enough to be vectorized.  */
-/* { dg-final { scan-tree-dump-times "basic block vectorized" 1
"slp1" { xfail { ! vect_peeling_profitable } } } } */

> Thanks,
> Bill
>
>
> 2018-02-02  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>
>         * g++.dg/vect/slp-pr56812.cc: Convert from DOS newline characters
>         to utf-8-unix.  Change to scan "optimized" dump for indications
>         that the code was vectorized.
>
>
> Index: gcc/testsuite/g++.dg/vect/slp-pr56812.cc
> ===================================================================
> --- gcc/testsuite/g++.dg/vect/slp-pr56812.cc    (revision 257352)
> +++ gcc/testsuite/g++.dg/vect/slp-pr56812.cc    (working copy)
> @@ -1,22 +1,31 @@
> -/* { dg-do compile } */
> -/* { dg-require-effective-target vect_float } */
> -/* { dg-require-effective-target vect_hw_misalign } */
> -/* { dg-additional-options "-O3 -funroll-loops -fvect-cost-model=dynamic" } */
> -
> -class mydata {
> -public:
> -    mydata() {Set(-1.0);}
> -    void Set (float);
> -    static int upper() {return 8;}
> -    float data[8];
> -};
> -
> -void mydata::Set (float x)
> -{
> -  for (int i=0; i<upper(); i++)
> -    data[i] = x;
> -}
> -
> -/* For targets without vector loop peeling the loop becomes cheap
> -   enough to be vectorized.  */
> -/* { dg-final { scan-tree-dump-times "basic block vectorized" 1 "slp1" { xfail { ! vect_peeling_profitable } } } } */
> +/* { dg-do compile } */
> +/* { dg-require-effective-target vect_float } */
> +/* { dg-require-effective-target vect_hw_misalign } */
> +/* { dg-additional-options "-O3 -funroll-loops -fvect-cost-model=dynamic -fdump-tree-optimized" } */
> +
> +class mydata {
> +public:
> +    mydata() {Set(-1.0);}
> +    void Set (float);
> +    static int upper() {return 8;}
> +    float data[8];
> +};
> +
> +void mydata::Set (float x)
> +{
> +  for (int i=0; i<upper(); i++)
> +    data[i] = x;
> +}
> +
> +/* { dg-final { scan-tree-dump "vect_cst__\[0-9\]* = " "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "= vect_cst__\[0-9\]*;" 2 "optimized" } } */
> +
> +/* Expected vectorized output is something like:
> +
> +  <bb 2> [11.11%]:
> +  vect_cst__10 = {x_5(D), x_5(D), x_5(D), x_5(D)};
> +  MEM[(float *)this_4(D)] = vect_cst__10;
> +  MEM[(float *)this_4(D) + 16B] = vect_cst__10;
> +  return;
> +
> +  Could be vectorized either by the "vect" or the "slp" pass.  */
>