From 508a909eca536f7f6a60af9bd7ecea761bd2e8f1 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Thu, 20 Sep 2018 12:58:16 +0000 Subject: [PATCH] Add missing alignment checks in epilogue loop vectorisation (PR 86877) Epilogue loop vectorisation skips vect_enhance_data_refs_alignment since it doesn't make sense to version or peel the epilogue loop (that will already have happened for the main loop). But this means that it also fails to check whether the accesses are suitably aligned for the new vector subarch. We don't seem to carry alignment information from the (potentially peeled or versioned) main loop to the epilogue loop, which would be good to fix at some point. I think we want this patch regardless, since there's no guarantee that the alignment requirements are the same for every subarch. 2018-09-20 Richard Sandiford gcc/ PR tree-optimization/86877 * tree-vect-loop.c (vect_analyze_loop_2): Call vect_verify_datarefs_alignment. gcc/testsuite/ PR tree-optimization/86877 * gfortran.dg/vect/vect-8-epilogue.F90: New test. From-SVN: r264439 --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 5 +++++ .../gfortran.dg/vect/vect-8-epilogue.F90 | 6 ++++++ gcc/tree-vect-loop.c | 21 ++++++++++--------- 4 files changed, 28 insertions(+), 10 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/vect/vect-8-epilogue.F90 diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 728799d70a6..af5fddf10ce 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2018-09-20 Richard Sandiford + + PR tree-optimization/86877 + * tree-vect-loop.c (vect_analyze_loop_2): Call + vect_verify_datarefs_alignment. + 2018-09-19 Marek Polacek * doc/invoke.texi: Document -Wclass-conversion. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 25f61d2f7f1..ade95dbb5c9 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-09-20 Richard Sandiford + + PR tree-optimization/86877 + * gfortran.dg/vect/vect-8-epilogue.F90: New test. + 2018-09-19 Marek Polacek * g++.dg/conversion/op4.C: Add dg-warning. diff --git a/gcc/testsuite/gfortran.dg/vect/vect-8-epilogue.F90 b/gcc/testsuite/gfortran.dg/vect/vect-8-epilogue.F90 new file mode 100644 index 00000000000..2a09539a510 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/vect/vect-8-epilogue.F90 @@ -0,0 +1,6 @@ +! { dg-do compile } +! { dg-require-effective-target vect_double } +! { dg-additional-options "-finline-matmul-limit=0 --param vect-epilogues-nomask=1" } +! { dg-additional-options "-mstrict-align" { target { aarch64*-*-* } } } + +#include "vect-8.f90" diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 640b0b9700c..70e9157646f 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -1979,20 +1979,21 @@ start_over: if (!ok) return false; - /* Do not invoke vect_enhance_data_refs_alignment for eplilogue - vectorization. */ + /* Do not invoke vect_enhance_data_refs_alignment for epilogue + vectorization, since we do not want to add extra peeling or + add versioning for alignment. */ if (!LOOP_VINFO_EPILOGUE_P (loop_vinfo)) - { /* This pass will decide on using loop versioning and/or loop peeling in order to enhance the alignment of data references in the loop. */ ok = vect_enhance_data_refs_alignment (loop_vinfo); - if (!ok) - { - if (dump_enabled_p ()) - dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, - "bad data alignment.\n"); - return false; - } + else + ok = vect_verify_datarefs_alignment (loop_vinfo); + if (!ok) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "bad data alignment.\n"); + return false; } if (slp) -- 2.30.2