| Message ID | f026396c-59b8-36ae-2332-e2ece6db2e3b@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | vect: Don't retry if the previous analysis fails | expand |
On Wed, May 17, 2023 at 8:06 AM Kewen.Lin <linkw@linux.ibm.com> wrote: > > Hi, > > When working on a cost tweaking patch, I found that a newly > added test case has different dumpings with stage-1 and > bootstrapped gcc. By looking into it, the apparent reason > is vect_analyze_loop_2 doesn't get slp_done_for_suggested_uf > set expectedly, the following retrying will use the garbage > slp_done_for_suggested_uf instead. In fact, the setting of > slp_done_for_suggested_uf only happens when the previous > analysis succeeds, for the mentioned test case, its previous > analysis does fail, it's unexpected to use the value of > slp_done_for_suggested_uf any more. > > In function vect_analyze_loop_1, we only return success when > res is true, which is the result of 1st analysis. It means > we never try to vectorize with unroll_vinfo if the previous > analysis fails. So this patch shouldn't break anything, and > just stop some useless analysis early. > > Bootstrapped and regtested on x86_64-redhat-linux, > aarch64-linux-gnu and powerpc64{,le}-linux-gnu. > > Is it ok for trunk? OK for trunk and affected branches. Richard. > BR, > Kewen > ----- > gcc/ChangeLog: > > * tree-vect-loop.cc (vect_analyze_loop_1): Don't retry analysis with > suggested unroll factor once the previous analysis fails. > --- > gcc/tree-vect-loop.cc | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > index ed0166fedab..905145ae97b 100644 > --- a/gcc/tree-vect-loop.cc > +++ b/gcc/tree-vect-loop.cc > @@ -3044,7 +3044,7 @@ vect_analyze_loop_1 (class loop *loop, vec_info_shared *shared, > res ? "succeeded" : " failed", > GET_MODE_NAME (loop_vinfo->vector_mode)); > > - if (!main_loop_vinfo && suggested_unroll_factor > 1) > + if (res && !main_loop_vinfo && suggested_unroll_factor > 1) > { > if (dump_enabled_p ()) > dump_printf_loc (MSG_NOTE, vect_location, > -- > 2.31.1
on 2023/5/17 14:32, Richard Biener wrote: > On Wed, May 17, 2023 at 8:06 AM Kewen.Lin <linkw@linux.ibm.com> wrote: >> >> Hi, >> >> When working on a cost tweaking patch, I found that a newly >> added test case has different dumpings with stage-1 and >> bootstrapped gcc. By looking into it, the apparent reason >> is vect_analyze_loop_2 doesn't get slp_done_for_suggested_uf >> set expectedly, the following retrying will use the garbage >> slp_done_for_suggested_uf instead. In fact, the setting of >> slp_done_for_suggested_uf only happens when the previous >> analysis succeeds, for the mentioned test case, its previous >> analysis does fail, it's unexpected to use the value of >> slp_done_for_suggested_uf any more. >> >> In function vect_analyze_loop_1, we only return success when >> res is true, which is the result of 1st analysis. It means >> we never try to vectorize with unroll_vinfo if the previous >> analysis fails. So this patch shouldn't break anything, and >> just stop some useless analysis early. >> >> Bootstrapped and regtested on x86_64-redhat-linux, >> aarch64-linux-gnu and powerpc64{,le}-linux-gnu. >> >> Is it ok for trunk? > > OK for trunk and affected branches. Pushed as r14-926 and backported in r13-7364 & r12-9633. Thanks! BR, Kewen
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index ed0166fedab..905145ae97b 100644 --- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -3044,7 +3044,7 @@ vect_analyze_loop_1 (class loop *loop, vec_info_shared *shared, res ? "succeeded" : " failed", GET_MODE_NAME (loop_vinfo->vector_mode)); - if (!main_loop_vinfo && suggested_unroll_factor > 1) + if (res && !main_loop_vinfo && suggested_unroll_factor > 1) { if (dump_enabled_p ()) dump_printf_loc (MSG_NOTE, vect_location,
Hi, When working on a cost tweaking patch, I found that a newly added test case has different dumpings with stage-1 and bootstrapped gcc. By looking into it, the apparent reason is vect_analyze_loop_2 doesn't get slp_done_for_suggested_uf set expectedly, the following retrying will use the garbage slp_done_for_suggested_uf instead. In fact, the setting of slp_done_for_suggested_uf only happens when the previous analysis succeeds, for the mentioned test case, its previous analysis does fail, it's unexpected to use the value of slp_done_for_suggested_uf any more. In function vect_analyze_loop_1, we only return success when res is true, which is the result of 1st analysis. It means we never try to vectorize with unroll_vinfo if the previous analysis fails. So this patch shouldn't break anything, and just stop some useless analysis early. Bootstrapped and regtested on x86_64-redhat-linux, aarch64-linux-gnu and powerpc64{,le}-linux-gnu. Is it ok for trunk? BR, Kewen ----- gcc/ChangeLog: * tree-vect-loop.cc (vect_analyze_loop_1): Don't retry analysis with suggested unroll factor once the previous analysis fails. --- gcc/tree-vect-loop.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.31.1