Fortran/OpenACC: Permit PARAMETER as 'var' in clauses (+ ignore)

It turned out that other compilers permit (require?) named constants
to appear in clauses - and programs actually use this. OpenACC 3.4
added therefore the following:
  In this spec, a _var_ (in italics) is one of the following:
  ...
  * a named constant in Fortran.
plus
  If during an optimization phase _var_ is removed by the compiler,
  appearances of var in data clauses are ignored.

Thus, all errors related to PARAMETER are now downgraded, most
to a -Wsurprising warning, but for 'acc declare device_resident'
(which kind of makes sense), no warning is printed.

In trans-openmp.cc, those are ignored, unless I missed some code
path. (If so, I hope the middle end removes them; but before
removing them for the covered cases, the program just compiled &
linked fine.)

Note that 'ignore PARAMETER inside clauses' in trans-openmp.cc
would in principle also apply to expressions ('if (var)') but
those should be evaluated during 'resolve.cc' + 'openmp.cc' to
their (numeric, logical, string) value such that there should
be no issue.

gcc/fortran/ChangeLog:

	* invoke.texi (-Wsurprising): Note about OpenACC warning
	related to PARAMATER.
	* openmp.cc (resolve_omp_clauses, gfc_resolve_oacc_declare):
	Accept PARAMETER for OpenACC but add surprising warning.
	* trans-openmp.cc (gfc_trans_omp_variable_list,
	gfc_trans_omp_clauses): Ignore PARAMETER inside clauses.

gcc/testsuite/ChangeLog:

	* gfortran.dg/goacc/parameter.f95: Add -Wsurprising flag
	and update expected diagnostic.
	* gfortran.dg/goacc/parameter-3.f90: New test.
	* gfortran.dg/goacc/parameter-4.f90: New test.

3 files changed, 56 insertions, 13 deletions

diff --git a/gcc/testsuite/gfortran.dg/goacc/parameter-3.f90 b/gcc/testsuite/gfortran.dg/goacc/parameter-3.f90
new file mode 100644
index 0000000..2c8aa61
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/goacc/parameter-3.f90
@@ -0,0 +1,16 @@
+! { dg-do compile }
+
+subroutine x
+  integer :: var
+  integer, parameter :: ilog = 0
+  integer, parameter :: array(*) = [11,22,33]
+  !$ACC DECLARE COPYIN(ilog, array, var, array) ! { dg-error "Symbol 'array' present on multiple clauses" }
+end subroutine x
+
+integer :: a
+integer, parameter :: b = 4
+integer, parameter :: c(*) = [1,2,3]
+
+!$acc parallel copy(a,c,b,c)  ! { dg-error "Symbol 'c' present on multiple clauses" }
+!$acc end parallel
+end
diff --git a/gcc/testsuite/gfortran.dg/goacc/parameter-4.f90 b/gcc/testsuite/gfortran.dg/goacc/parameter-4.f90
new file mode 100644
index 0000000..aadd7cf
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/goacc/parameter-4.f90
@@ -0,0 +1,26 @@
+! { dg-do compile }
+! { dg-additional-options "-fdump-tree-original" }
+
+subroutine x
+  integer :: var
+  integer, parameter :: ilog = 0
+  integer, parameter :: array(*) = [11,22,33]
+  !$ACC DECLARE COPYIN(ilog, array, var)
+end subroutine x
+
+integer :: a
+integer, parameter :: b = 4
+integer, parameter :: c(*) = [1,2,3]
+
+!$acc parallel copy(a,c,b)
+  a = c(2) + b
+!$acc end parallel
+
+!$acc parallel firstprivate(a,c,b)
+  a = c(2) + b
+!$acc end parallel
+end
+
+! { dg-final { scan-tree-dump-times "#pragma acc data map\\(to:var\\)" 1 "original" } }
+! { dg-final { scan-tree-dump-times "#pragma acc parallel map\\(tofrom:a\\)" 1 "original" } }
+! { dg-final { scan-tree-dump-times "#pragma acc parallel firstprivate\\(a\\)" 1 "original" } }
diff --git a/gcc/testsuite/gfortran.dg/goacc/parameter.f95 b/gcc/testsuite/gfortran.dg/goacc/parameter.f95
index b581338..a9bde4a 100644
--- a/gcc/testsuite/gfortran.dg/goacc/parameter.f95
+++ b/gcc/testsuite/gfortran.dg/goacc/parameter.f95
@@ -1,4 +1,5 @@
 ! { dg-do compile } 
+! { dg-additional-options "-Wsurprising" }
 
 module test
 contains
@@ -6,37 +7,37 @@ contains
     implicit none
     integer :: i
     integer, parameter :: a = 1
-    !$acc declare device_resident (a) ! { dg-error "is not a variable" }
-    !$acc data copy (a) ! { dg-error "not a variable" }
+    !$acc declare device_resident (a) ! (no warning here - for semi-good reasons)
+    !$acc data copy (a)  ! { dg-warning "Clause for object 'a' at .1. is ignored as parameters need not be copied \\\[-Wsurprising\\\]" }
     !$acc end data
-    !$acc data deviceptr (a) ! { dg-error "not a variable" }
+    !$acc data deviceptr (a)  ! { dg-warning "Clause for object 'a' at .1. is ignored as parameters need not be copied \\\[-Wsurprising\\\]" }
     !$acc end data
-    !$acc parallel private (a) ! { dg-error "not a variable" }
+    !$acc parallel private (a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     !$acc end parallel
-    !$acc serial private (a) ! { dg-error "not a variable" }
+    !$acc serial private (a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     !$acc end serial
-    !$acc host_data use_device (a) ! { dg-error "not a variable" }
+    !$acc host_data use_device (a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     !$acc end host_data
-    !$acc parallel loop reduction(+:a) ! { dg-error "not a variable" }
+    !$acc parallel loop reduction(+:a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     do i = 1,5
     enddo
     !$acc end parallel loop
-    !$acc serial loop reduction(+:a) ! { dg-error "not a variable" }
+    !$acc serial loop reduction(+:a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     do i = 1,5
     enddo
     !$acc end serial loop
     !$acc parallel loop
     do i = 1,5
-      !$acc cache (a) ! { dg-error "not a variable" }
+      !$acc cache (a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     enddo
     !$acc end parallel loop
     !$acc serial loop
     do i = 1,5
-      !$acc cache (a) ! { dg-error "not a variable" }
+      !$acc cache (a) ! { dg-warning "Clause for object 'a' at .1. is ignored as it is a parameter \\\[-Wsurprising\\\]" }
     enddo
     !$acc end serial loop
-    !$acc update device (a) ! { dg-error "not a variable" }
-    !$acc update host (a) ! { dg-error "not a variable" }
-    !$acc update self (a) ! { dg-error "not a variable" }
+    !$acc update device (a)  ! { dg-warning "Clause for object 'a' at .1. is ignored as parameters need not be copied \\\[-Wsurprising\\\]" }
+    !$acc update host (a)  ! { dg-warning "Clause for object 'a' at .1. is ignored as parameters need not be copied \\\[-Wsurprising\\\]" }
+    !$acc update self (a)  ! { dg-warning "Clause for object 'a' at .1. is ignored as parameters need not be copied \\\[-Wsurprising\\\]" }
   end subroutine oacc1
 end module test