OpenACC: Don't gang-privatize artificial variables [PR90115]

This patch prevents compiler-generated artificial variables from being
treated as privatization candidates for OpenACC.

The rationale is that e.g. "gang-private" variables actually must be
shared by each worker and vector spawned within a particular gang, but
that sharing is not necessary for any compiler-generated variable (at
least at present, but no such need is anticipated either).  Variables on
the stack (and machine registers) are already private per-"thread"
(gang, worker and/or vector), and that's fine for artificial variables.

We're restricting this to blocks, as we still need to understand what it
means for a 'DECL_ARTIFICIAL' to appear in a 'private' clause.

Several tests need their scan output patterns adjusted to compensate.

2022-10-14  Julian Brown  <julian@codesourcery.com>

	PR middle-end/90115
gcc/
	* omp-low.cc (oacc_privatization_candidate_p): Artificial vars are not
	privatization candidates.

libgomp/
	* testsuite/libgomp.oacc-fortran/declare-1.f90: Adjust scan output.
	* testsuite/libgomp.oacc-fortran/host_data-5.F90: Likewise.
	* testsuite/libgomp.oacc-fortran/if-1.f90: Likewise.
	* testsuite/libgomp.oacc-fortran/print-1.f90: Likewise.
	* testsuite/libgomp.oacc-fortran/privatized-ref-2.f90: Likewise.

Co-authored-by: Thomas Schwinge <thomas@codesourcery.com>

diff --git a/gcc/omp-low.cc b/gcc/omp-low.cc
index a8809739001cc4e4a7f3c904e0bfe479cfec3369..82a93d00f67f6660955b3fa11ca6a8471d31a142 100644 (file)
--- a/gcc/omp-low.cc
+++ b/gcc/omp-low.cc
@@ -10710,6 +10710,28 @@ oacc_privatization_candidate_p (const location_t loc, const tree c,
        }
     }
 
+  /* If an artificial variable has been added to a bind, e.g.
+     a compiler-generated temporary structure used by the Fortran front-end, do
+     not consider it as a privatization candidate.  Note that variables on
+     the stack are private per-thread by default: making them "gang-private"
+     for OpenACC actually means to share a single instance of a variable
+     amongst all workers and threads spawned within each gang.
+     At present, no compiler-generated artificial variables require such
+     sharing semantics, so this is safe.  */
+
+  if (res && block && DECL_ARTIFICIAL (decl))
+    {
+      res = false;
+
+      if (dump_enabled_p ())
+       {
+         oacc_privatization_begin_diagnose_var (l_dump_flags, loc, c, decl);
+         dump_printf (l_dump_flags,
+                      "isn%'t candidate for adjusting OpenACC privatization "
+                      "level: %s\n", "artificial");
+       }
+    }
+
   if (res)
     {
       if (dump_enabled_p ())

diff --git a/libgomp/testsuite/libgomp.oacc-fortran/declare-1.f90 b/libgomp/testsuite/libgomp.oacc-fortran/declare-1.f90
index 51776a1d260ec46fac6ca81425ac778ae81419ce..89bd4a2d0945ffc3e5c85e458eacf0daf4766adf 100644 (file)
--- a/libgomp/testsuite/libgomp.oacc-fortran/declare-1.f90
+++ b/libgomp/testsuite/libgomp.oacc-fortran/declare-1.f90
@@ -215,7 +215,7 @@ program main
   ! { dg-note {variable 'C\.[0-9]+' declared in block potentially has improper OpenACC privatization level: 'const_decl'} "TODO" { target *-*-* } .-1 }
   ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-2 }
   ! { dg-note {variable 'S\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-3 }
-  ! { dg-note {variable 'desc\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-4 }
+  ! { dg-note {variable 'desc\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-4 }
   use vars
   use openacc
   implicit none

diff --git a/libgomp/testsuite/libgomp.oacc-fortran/host_data-5.F90 b/libgomp/testsuite/libgomp.oacc-fortran/host_data-5.F90
index 93e9ee09818dcd0e5a9f36d3dab8692e50e90148..c3453a579aea14b653b81b84733f8666c2741e07 100644 (file)
--- a/libgomp/testsuite/libgomp.oacc-fortran/host_data-5.F90
+++ b/libgomp/testsuite/libgomp.oacc-fortran/host_data-5.F90
@@ -43,7 +43,7 @@ subroutine foo (p2, parr, host_p, host_parr, cond)
   ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target { ! openacc_host_selected } } .-2 }
   ! { dg-note {variable 'p\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-3 }
   ! { dg-note {variable 'parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-4 }
-  ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target { ! openacc_host_selected } } .-5 }
+  ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-5 }
 #if !ACC_MEM_SHARED
     if (acc_is_present(p, c_sizeof(p))) stop 5
     if (acc_is_present(parr, 1)) stop 6
@@ -54,8 +54,8 @@ subroutine foo (p2, parr, host_p, host_parr, cond)
     ! { dg-note {variable 'host_p\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-3 }
     ! { dg-note {variable 'parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-4 }
     ! { dg-note {variable 'host_parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-5 }
-    ! { dg-note {variable 'D\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-6 }
-    ! { dg-note {variable 'transfer\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-7 }
+    ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-6 }
+    ! { dg-note {variable 'transfer\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-7 }
     ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-8 }
       ! not mapped yet, so it will be equal to the host pointer.
       if (transfer(c_loc(p), host_p) /= host_p) stop 7
@@ -74,9 +74,9 @@ subroutine foo (p2, parr, host_p, host_parr, cond)
     ! { dg-note {variable 'host_p\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-5 }
     ! { dg-note {variable 'host_parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-6 }
     ! { dg-note {variable 'C\.[0-9]+' declared in block potentially has improper OpenACC privatization level: 'const_decl'} "TODO" { target *-*-* } .-7 }
-    ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-8 }
-    ! { dg-note {variable 'D\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-9 }
-    ! { dg-note {variable 'transfer\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-10 }
+    ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-8 }
+    ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-9 }
+    ! { dg-note {variable 'transfer\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-10 }
     ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-11 }
       if (.not. acc_is_present(p, c_sizeof(p))) stop 11
       if (.not. acc_is_present(parr, 1)) stop 12
@@ -90,8 +90,8 @@ subroutine foo (p2, parr, host_p, host_parr, cond)
       ! { dg-note {variable 'host_p\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-3 }
       ! { dg-note {variable 'parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-4 }
       ! { dg-note {variable 'host_parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-5 }
-      ! { dg-note {variable 'D\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-6 }
-      ! { dg-note {variable 'transfer\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-7 }
+      ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-6 }
+      ! { dg-note {variable 'transfer\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-7 }
       ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-8 }
 #if ACC_MEM_SHARED
         if (transfer(c_loc(p), host_p) /= host_p) stop 15
@@ -110,8 +110,8 @@ subroutine foo (p2, parr, host_p, host_parr, cond)
         ! { dg-note {variable 'parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-4 }
         ! { dg-note {variable 'host_parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-5 }
         ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-6 }
-        ! { dg-note {variable 'D\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-7 }
-        ! { dg-note {variable 'transfer\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-8 }
+        ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-7 }
+        ! { dg-note {variable 'transfer\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-8 }
 #if ACC_MEM_SHARED
         if (transfer(c_loc(p), host_p) /= host_p) stop 19
         if (transfer(c_loc(parr), host_parr) /= host_parr) stop 20
@@ -129,8 +129,8 @@ subroutine foo (p2, parr, host_p, host_parr, cond)
         ! { dg-note {variable 'parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-4 }
         ! { dg-note {variable 'host_parr\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-5 }
         ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-6 }
-        ! { dg-note {variable 'D\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-7 }
-        ! { dg-note {variable 'transfer\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "TODO" { target *-*-* } .-8 }
+        ! { dg-note {variable 'D\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-7 }
+        ! { dg-note {variable 'transfer\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } .-8 }
 #if ACC_MEM_SHARED
         if (transfer(c_loc(p), host_p) /= host_p) stop 23
         if (transfer(c_loc(parr), host_parr) /= host_parr) stop 24

diff --git a/libgomp/testsuite/libgomp.oacc-fortran/if-1.f90 b/libgomp/testsuite/libgomp.oacc-fortran/if-1.f90
index c6d67647d4a4f8ae49d1c4a3113e12a8cd730867..e0cfd912d0fe26d304acb4efaffbfffbd7480047 100644 (file)
--- a/libgomp/testsuite/libgomp.oacc-fortran/if-1.f90
+++ b/libgomp/testsuite/libgomp.oacc-fortran/if-1.f90
@@ -382,7 +382,7 @@ program main
   b(:) = 1.0
 
   !$acc data copyin (a(1:N)) copyout (b(1:N)) if (0 == 1)
-  ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target { ! openacc_host_selected } } .-1 }
+  ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-1 }
 
 #if !ACC_MEM_SHARED
   if (acc_is_present (a) .eqv. .TRUE.) STOP 21
@@ -396,7 +396,7 @@ program main
 
   !$acc data copyin (a(1:N)) if (1 == 1)
   ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-1 }
-  ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target { ! openacc_host_selected } } .-2 }
+  ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-2 }
 
 #if !ACC_MEM_SHARED
     if (acc_is_present (a) .eqv. .FALSE.) STOP 23
@@ -404,7 +404,7 @@ program main
 
     !$acc data copyout (b(1:N)) if (0 == 1)
     ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-1 }
-    ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target { ! openacc_host_selected } } .-2 }
+    ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-2 }
 #if !ACC_MEM_SHARED
       if (acc_is_present (b) .eqv. .TRUE.) STOP 24
 #endif
@@ -877,7 +877,7 @@ program main
   b(:) = 1.0
 
   !$acc data copyin (a(1:N)) copyout (b(1:N)) if (0 == 1)
-  ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target { ! openacc_host_selected } } .-1 }
+  ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-1 }
 
 #if !ACC_MEM_SHARED
   if (acc_is_present (a) .eqv. .TRUE.) STOP 56
@@ -891,7 +891,7 @@ program main
 
   !$acc data copyin (a(1:N)) if (1 == 1)
   ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-1 }
-  ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target { ! openacc_host_selected } } .-2 }
+  ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-2 }
 
 #if !ACC_MEM_SHARED
     if (acc_is_present (a) .eqv. .FALSE.) STOP 58
@@ -899,7 +899,7 @@ program main
 
     !$acc data copyout (b(1:N)) if (0 == 1)
     ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: not addressable} "" { target *-*-* } .-1 }
-    ! { dg-note {variable 'parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target { ! openacc_host_selected } } .-2 }
+    ! { dg-note {variable 'parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target { ! openacc_host_selected } } .-2 }
 #if !ACC_MEM_SHARED
       if (acc_is_present (b) .eqv. .TRUE.) STOP 59
 #endif

diff --git a/libgomp/testsuite/libgomp.oacc-fortran/print-1.f90 b/libgomp/testsuite/libgomp.oacc-fortran/print-1.f90
index 42a8538e1fb386f05d2e095848696cde55333003..d2f89d915f8901a0455ebc0122f495850f91be50 100644 (file)
--- a/libgomp/testsuite/libgomp.oacc-fortran/print-1.f90
+++ b/libgomp/testsuite/libgomp.oacc-fortran/print-1.f90
@@ -6,15 +6,6 @@
 ! Separate file 'print-1-nvptx.f90' for nvptx offloading.
 ! { dg-skip-if "separate file" { offload_target_nvptx } }
 
-! For GCN offloading compilation, when gang-privatizing 'dt_parm.N'
-! (see below), we run into an 'gang-private data-share memory exhausted'
-! error: the default '-mgang-private-size' is too small.  Per
-! 'gcc/fortran/trans-io.cc'/'libgfortran/io/io.h', that one is
-! 'struct st_parameter_dt', which indeed is rather big.  Instead of
-! working out its exact size (which may vary per GCC configuration),
-! raise '-mgang-private-size' to an arbitrary high value.
-! { dg-additional-options "-foffload-options=amdgcn-amdhsa=-mgang-private-size=13579" { target openacc_radeon_accel_selected } }
-
 ! { dg-additional-options "-fopt-info-note-omp" }
 ! { dg-additional-options "-foffload=-fopt-info-note-omp" }
 
@@ -36,9 +27,7 @@ program main
   integer :: var = 42
 
 !$acc parallel ! { dg-line l_compute[incr c_compute] }
-  ! { dg-note {variable 'dt_parm\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} {} { target *-*-* } l_compute$c_compute }
-  !   { dg-note {variable 'dt_parm\.[0-9]+' ought to be adjusted for OpenACC privatization level: 'gang'} {} { target *-*-* } l_compute$c_compute }
-  !   { dg-note {variable 'dt_parm\.[0-9]+' adjusted for OpenACC privatization level: 'gang'} {} { target { ! openacc_host_selected } } l_compute$c_compute }
+  ! { dg-note {variable 'dt_parm\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} {} { target *-*-* } l_compute$c_compute }
   write (0, '("The answer is ", I2)') var
 !$acc end parallel
 

diff --git a/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-2.f90 b/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-2.f90
index b31f4066152b11123946eead5296be5184000788..498ef70b63a4ae977d11c4341f16d2443334c714 100644 (file)
--- a/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-2.f90
+++ b/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-2.f90
@@ -122,9 +122,7 @@ contains
     ! { dg-note {variable 'str' in 'private' clause is candidate for adjusting OpenACC privatization level} "" { target *-*-* } l_loop$c_loop }
     ! { dg-note {variable 'str' ought to be adjusted for OpenACC privatization level: 'gang'} "" { target *-*-* } l_loop$c_loop }
     ! { dg-note {variable 'str' adjusted for OpenACC privatization level: 'gang'} "" { target { ! { openacc_host_selected || { openacc_nvidia_accel_selected && __OPTIMIZE__ } } } } l_loop$c_loop }
-    ! { dg-note {variable 'char\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target *-*-* } l_loop$c_loop }
-    ! { dg-note {variable 'char\.[0-9]+' ought to be adjusted for OpenACC privatization level: 'gang'} "" { target *-*-* } l_loop$c_loop }
-    ! { dg-note {variable 'char\.[0-9]+' adjusted for OpenACC privatization level: 'gang'} "" { target { ! { openacc_host_selected || { openacc_nvidia_accel_selected && __OPTIMIZE__ } } } } l_loop$c_loop }
+    ! { dg-note {variable 'char\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } l_loop$c_loop }
     ! { dg-message {sorry, unimplemented: target cannot support alloca} PR65181 { target openacc_nvidia_accel_selected } l_loop$c_loop }
     do i = 1, 10
       str(i:i) = achar(ichar('A') + i)
@@ -167,9 +165,7 @@ contains
     ! { dg-note {variable 'scalar' in 'private' clause is candidate for adjusting OpenACC privatization level} "" { target *-*-* } l_loop$c_loop }
     ! { dg-note {variable 'scalar' ought to be adjusted for OpenACC privatization level: 'gang'} "" { target *-*-* } l_loop$c_loop }
     ! { dg-note {variable 'scalar' adjusted for OpenACC privatization level: 'gang'} "" { target { ! { openacc_host_selected || { openacc_nvidia_accel_selected && __OPTIMIZE__ } } } } l_loop$c_loop }
-    ! { dg-note {variable 'char\.[0-9]+' declared in block is candidate for adjusting OpenACC privatization level} "" { target *-*-* } l_loop$c_loop }
-    ! { dg-note {variable 'char\.[0-9]+' ought to be adjusted for OpenACC privatization level: 'gang'} "" { target *-*-* } l_loop$c_loop }
-    ! { dg-note {variable 'char\.[0-9]+' adjusted for OpenACC privatization level: 'gang'} "" { target { ! { openacc_host_selected || { openacc_nvidia_accel_selected && __OPTIMIZE__ } } } } l_loop$c_loop }
+    ! { dg-note {variable 'char\.[0-9]+' declared in block isn't candidate for adjusting OpenACC privatization level: artificial} "" { target *-*-* } l_loop$c_loop }
     do i = 1, 15
       scalar(i:i) = achar(ichar('A') + i)
     end do