| Message ID | patch-18251-tamar@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | middle-end: don't cache restart_loop in vectorizable_live_operations [PR113808] | expand |
On Thu, 8 Feb 2024, Tamar Christina wrote: > Hi All, > > There's a bug in vectorizable_live_operation that restart_loop is defined > outside the loop. > > This variable is supposed to indicate whether we are doing a first or last > index reduction. The problem is that by defining it outside the loop it becomes > dependent on the order we visit the USE/DEFs. > > In the given example, the loop isn't PEELED, but we visit the early exit uses > first. This then sets the boolean to true and it can't get to false again. > > So when we visit the main exit we still treat it as an early exit for that > SSA name. > > This cleans it up and renames the variables to something that's hopefully > clearer to their intention. > > Bootstrapped Regtested on aarch64-none-linux-gnu and > x86_64-pc-linux-gnu no issues. > > Ok for master? OK. Thanks, Richard. > Thanks, > Tamar > > gcc/ChangeLog: > > PR tree-optimization/113808 > * tree-vect-loop.cc (vectorizable_live_operation): Don't cache the > value cross iterations. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/113808 > * gfortran.dg/vect/vect-early-break_1-PR113808.f90: New test. > > --- inline copy of patch -- > diff --git a/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 > new file mode 100644 > index 0000000000000000000000000000000000000000..5c339fa7a348fac5527bbbf456a535da96b5c1ed > --- /dev/null > +++ b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 > @@ -0,0 +1,21 @@ > +! { dg-add-options vect_early_break } > +! { dg-require-effective-target vect_early_break } > +! { dg-require-effective-target vect_long_long } > +! { dg-additional-options "-fopenmp-simd" } > + > +! { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } > + > +program main > + integer :: n, i,k > + n = 11 > + do i = 1, n,2 > + !$omp simd lastprivate(k) > + do k = 1, i + 41 > + if (k > 11 + 41 .or. k < 1) error stop > + end do > + end do > + if (k /= 53) then > + print *, k, 53 > + error stop > + endif > +end > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > index 190df9ec7741fd05aa0b9abe150baf06b2ca9a57..eed2268e9bae7e7ad36d13da03e0b54eab26ef6f 100644 > --- a/gcc/tree-vect-loop.cc > +++ b/gcc/tree-vect-loop.cc > @@ -10950,7 +10950,7 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, > did. For the live values we want the value at the start of the iteration > rather than at the end. */ > edge main_e = LOOP_VINFO_IV_EXIT (loop_vinfo); > - bool restart_loop = LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo); > + bool all_exits_as_early_p = LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo); > FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, lhs) > if (!is_gimple_debug (use_stmt) > && !flow_bb_inside_loop_p (loop, gimple_bb (use_stmt))) > @@ -10966,8 +10966,7 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, > /* For early exit where the exit is not in the BB that leads > to the latch then we're restarting the iteration in the > scalar loop. So get the first live value. */ > - restart_loop = restart_loop || !main_exit_edge; > - if (restart_loop > + if ((all_exits_as_early_p || !main_exit_edge) > && STMT_VINFO_DEF_TYPE (stmt_info) == vect_induction_def) > { > tmp_vec_lhs = vec_lhs0; > > > > >
On Thu, Feb 08, 2024 at 10:37:14AM +0000, Tamar Christina wrote: > PR tree-optimization/113808 > * tree-vect-loop.cc (vectorizable_live_operation): Don't cache the > value cross iterations. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/113808 > * gfortran.dg/vect/vect-early-break_1-PR113808.f90: New test. Please use lowercase pr instead of PR for consistency with all the other tests in the directory. > --- inline copy of patch -- > diff --git a/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 > new file mode 100644 > index 0000000000000000000000000000000000000000..5c339fa7a348fac5527bbbf456a535da96b5c1ed > --- /dev/null > +++ b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 > @@ -0,0 +1,21 @@ > +! { dg-add-options vect_early_break } > +! { dg-require-effective-target vect_early_break } > +! { dg-require-effective-target vect_long_long } > +! { dg-additional-options "-fopenmp-simd" } > + > +! { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } > + > +program main > + integer :: n, i,k > + n = 11 > + do i = 1, n,2 > + !$omp simd lastprivate(k) Please either drop lastprivate(k) clause or use linear(k:1) The iteration var of simd loop without collapse or with collapse(1) is implicitly linear with the step, and even linear means the value from the last iteration can be used after the simd construct. Overriding the data sharing to something different has been only added recently to OpenMP and isn't really needed here. > + do k = 1, i + 41 > + if (k > 11 + 41 .or. k < 1) error stop > + end do > + end do > + if (k /= 53) then > + print *, k, 53 > + error stop > + endif > +end Jakub
> Please either drop lastprivate(k) clause or use linear(k:1) > The iteration var of simd loop without collapse or with > collapse(1) is implicitly linear with the step, and even linear > means the value from the last iteration can be used after the > simd construct. Overriding the data sharing to something different > has been only added recently to OpenMP and isn't really needed here. > Sorry I know very little about fortran, is this ok? Regtested on aarch64-none-linux-gnu and no issues. Ok for master? Thanks, Tamar gcc/testsuite/ChangeLog: PR tree-optimization/113808 * gfortran.dg/vect/vect-early-break_1-PR113808.f90: Moved to... * gfortran.dg/vect/vect-early-break_1-pr113808.f90: ...here. --- inline copy of patch --- diff --git a/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-pr113808.f90 similarity index 93% rename from gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 rename to gcc/testsuite/gfortran.dg/vect/vect-early-break_1-pr113808.f90 index 5c339fa7a348fac5527bbbf456a535da96b5c1ed..6f92e9095bdee08a5a9db2816f57da6c14d91b11 100644 --- a/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 +++ b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-pr113808.f90 @@ -9,7 +9,7 @@ program main integer :: n, i,k n = 11 do i = 1, n,2 - !$omp simd lastprivate(k) + !$omp simd do k = 1, i + 41 if (k > 11 + 41 .or. k < 1) error stop end do
On Thu, Feb 08, 2024 at 10:54:07AM +0000, Tamar Christina wrote: > > Please either drop lastprivate(k) clause or use linear(k:1) > > The iteration var of simd loop without collapse or with > > collapse(1) is implicitly linear with the step, and even linear > > means the value from the last iteration can be used after the > > simd construct. Overriding the data sharing to something different > > has been only added recently to OpenMP and isn't really needed here. > > > > Sorry I know very little about fortran, is this ok? > > Regtested on aarch64-none-linux-gnu and no issues. > > Ok for master? > > Thanks, > Tamar > > gcc/testsuite/ChangeLog: > > PR tree-optimization/113808 > * gfortran.dg/vect/vect-early-break_1-PR113808.f90: Moved to... > * gfortran.dg/vect/vect-early-break_1-pr113808.f90: ...here. Yes, thanks. Jakub
--- /dev/null +++ b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 @@ -0,0 +1,21 @@ +! { dg-add-options vect_early_break } +! { dg-require-effective-target vect_early_break } +! { dg-require-effective-target vect_long_long } +! { dg-additional-options "-fopenmp-simd" } + +! { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } + +program main + integer :: n, i,k + n = 11 + do i = 1, n,2 + !$omp simd lastprivate(k) + do k = 1, i + 41 + if (k > 11 + 41 .or. k < 1) error stop + end do + end do + if (k /= 53) then + print *, k, 53 + error stop + endif +end diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index 190df9ec7741fd05aa0b9abe150baf06b2ca9a57..eed2268e9bae7e7ad36d13da03e0b54eab26ef6f 100644 --- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -10950,7 +10950,7 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, did. For the live values we want the value at the start of the iteration rather than at the end. */ edge main_e = LOOP_VINFO_IV_EXIT (loop_vinfo); - bool restart_loop = LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo); + bool all_exits_as_early_p = LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo); FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, lhs) if (!is_gimple_debug (use_stmt) && !flow_bb_inside_loop_p (loop, gimple_bb (use_stmt))) @@ -10966,8 +10966,7 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, /* For early exit where the exit is not in the BB that leads to the latch then we're restarting the iteration in the scalar loop. So get the first live value. */ - restart_loop = restart_loop || !main_exit_edge; - if (restart_loop + if ((all_exits_as_early_p || !main_exit_edge) && STMT_VINFO_DEF_TYPE (stmt_info) == vect_induction_def) { tmp_vec_lhs = vec_lhs0;
Hi All, There's a bug in vectorizable_live_operation that restart_loop is defined outside the loop. This variable is supposed to indicate whether we are doing a first or last index reduction. The problem is that by defining it outside the loop it becomes dependent on the order we visit the USE/DEFs. In the given example, the loop isn't PEELED, but we visit the early exit uses first. This then sets the boolean to true and it can't get to false again. So when we visit the main exit we still treat it as an early exit for that SSA name. This cleans it up and renames the variables to something that's hopefully clearer to their intention. Bootstrapped Regtested on aarch64-none-linux-gnu and x86_64-pc-linux-gnu no issues. Ok for master? Thanks, Tamar gcc/ChangeLog: PR tree-optimization/113808 * tree-vect-loop.cc (vectorizable_live_operation): Don't cache the value cross iterations. gcc/testsuite/ChangeLog: PR tree-optimization/113808 * gfortran.dg/vect/vect-early-break_1-PR113808.f90: New test. --- inline copy of patch -- diff --git a/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 new file mode 100644 index 0000000000000000000000000000000000000000..5c339fa7a348fac5527bbbf456a535da96b5c1ed -- diff --git a/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 new file mode 100644 index 0000000000000000000000000000000000000000..5c339fa7a348fac5527bbbf456a535da96b5c1ed --- /dev/null +++ b/gcc/testsuite/gfortran.dg/vect/vect-early-break_1-PR113808.f90 @@ -0,0 +1,21 @@ +! { dg-add-options vect_early_break } +! { dg-require-effective-target vect_early_break } +! { dg-require-effective-target vect_long_long } +! { dg-additional-options "-fopenmp-simd" } + +! { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" } } + +program main + integer :: n, i,k + n = 11 + do i = 1, n,2 + !$omp simd lastprivate(k) + do k = 1, i + 41 + if (k > 11 + 41 .or. k < 1) error stop + end do + end do + if (k /= 53) then + print *, k, 53 + error stop + endif +end diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index 190df9ec7741fd05aa0b9abe150baf06b2ca9a57..eed2268e9bae7e7ad36d13da03e0b54eab26ef6f 100644 --- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -10950,7 +10950,7 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, did. For the live values we want the value at the start of the iteration rather than at the end. */ edge main_e = LOOP_VINFO_IV_EXIT (loop_vinfo); - bool restart_loop = LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo); + bool all_exits_as_early_p = LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo); FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, lhs) if (!is_gimple_debug (use_stmt) && !flow_bb_inside_loop_p (loop, gimple_bb (use_stmt))) @@ -10966,8 +10966,7 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, /* For early exit where the exit is not in the BB that leads to the latch then we're restarting the iteration in the scalar loop. So get the first live value. */ - restart_loop = restart_loop || !main_exit_edge; - if (restart_loop + if ((all_exits_as_early_p || !main_exit_edge) && STMT_VINFO_DEF_TYPE (stmt_info) == vect_induction_def) { tmp_vec_lhs = vec_lhs0;