[flang][OpenMP] Add parsing support for nontemporal clause.

[arnamoy10]

Summary

This patch adds parsing support for the nontemporal clause. Also adds a couple of test cases.

[clementval]

flang/include/flang/Parser/dump-parse-tree.h

503 ↗

(On Diff #362096)

Non necessary with update to OMP.td

flang/include/flang/Parser/parse-tree.h

3380 ↗

(On Diff #362096)

Non necessary with update to OMP.td

flang/lib/Parser/unparse.cpp

1993 ↗

(On Diff #362096)

If you update the OMP.td as mentioned below, the unpausing will be done automatically.

flang/lib/Semantics/check-omp-structure.cpp

1428 ↗

(On Diff #362096)

Why removing the CHECK_SIMPLE_CLAUSE that is doing this already?

llvm/include/llvm/Frontend/OpenMP/OMP.td

264

You should be able to avoid a specific node by using this:

let flangClass = "Name";
let isValueList = true;

is_device_ptr, uniform and use_device_ptr are using this already.

[arnamoy10]

flang/include/flang/Parser/parse-tree.h

3380 ↗

(On Diff #362096)

Thanks for the comments. However, are you sure about the removal of this struct definition? Because now from flang/lib/Parser/openmp-parsers.cpp, I am getting the following error:

flang/lib/Parser/openmp-parsers.cpp:153:23: error: ‘OmpNontemporalClause’ was not declared in this scope 
153 | TYPE_PARSER(construct<OmpNontemporalClause>(nonemptyList(name)))

Thanks for the help.

[clementval]

flang/include/flang/Parser/parse-tree.h

3380 ↗

(On Diff #362096)

Yeah but you have to remove it everywhere. Your parser will be parenthesized(nonemptyList(name)).

[clementval]

flang/lib/Parser/openmp-parsers.cpp

207

[arnamoy10]

flang/lib/Parser/openmp-parsers.cpp

207

Thank you. With your suggested change, I do not get error while building the compiler, but I get the following error while running -fopenmp -fsyntax-only on the examples I provide. Here is the error:

error: Internal: no symbol found for 'a'
!$omp target teams distribute simd nontemporal(a)
                                                  ^

What am I missing here?

[clementval]

flang/lib/Parser/openmp-parsers.cpp

207

This error is coming from the name resolution. So basically your semantic is fine but after the semantic the name resolution fails since nontemporal is not in it. You can look at flang/lib/Semantics/resolve-directives.cpp and look what is done in the two example below:

https://github.com/llvm/llvm-project/blob/ec1a49170129ddb62f268ff0b3f12b3d09987a7e/flang/lib/Semantics/resolve-directives.cpp#L363
https://github.com/llvm/llvm-project/blob/ec1a49170129ddb62f268ff0b3f12b3d09987a7e/flang/lib/Semantics/resolve-directives.cpp#L405

[arnamoy10]

flang/lib/Parser/openmp-parsers.cpp

207

Thanks for the pointer. But as you look in the patch, I am adding a call to ResolveOmpNameList in flang/lib/Semantics/resolve-directives.cpp, similar to what you indicated. But why I am still getting error?

[clementval]

flang/lib/Parser/openmp-parsers.cpp

207

DId you change the signature? It should be in the bool Pre(const parser::OmpClause::Nontemporal &x) after the correct change to OMP.td. OmpNontemporalClause should not present anymore.

[arnamoy10]

flang/lib/Parser/openmp-parsers.cpp

207

Thanks for the comment. However, if I change the signature, I am not able to use ResolveOmpNameList() similar to a case as per your previous suggestion here How do I do the name resolution then?

[clementval]

flang/lib/Parser/openmp-parsers.cpp

207

You probably need to change a bit the code to retrieve the name list.

Should probably look like this: https://github.com/llvm/llvm-project/blob/ec1a49170129ddb62f268ff0b3f12b3d09987a7e/flang/lib/Semantics/resolve-directives.cpp#L405

There are other clauses with name list so basically doing the same as those clauses will work.

[arnamoy10]

flang/lib/Parser/openmp-parsers.cpp

207

Thanks for the comment. However all the other clauses that deal with Namelist have a struct definition in flang/include/flang/Parser/parse-tree.h, with a memebr in them that holds the list of names (e.g. here, here. However, as per your suggestions, we do not need a struct definition with update to Omp.td. I am finding this contradictory.

[clementval]

flang/lib/Parser/openmp-parsers.cpp

207

This is not true. use_device_ptr and is_device_ptr are two examples that deal with name list and use the TableGen file the right way. Other clause that have a struct are probably something leftover from when we moved to TableGen and we should correct them as well. There is no need os an extra struct for these clauses and that not how the TableGen file should be used.

[arnamoy10]

flang/lib/Parser/openmp-parsers.cpp

207

Thank you. I tried to resolve the name list inspired by this code as the following:

const auto &nontemporalNameList{x.v};
ResolveOmpNameList(nontemporalNameList, Symbol::Flag::OmpNontemporal);

However, while compiling I get the following error now:

llvm-project/build/bin/flang: line 415: lib_files[@]: unbound variable

What I might be doing wrong?

I could not find how name list is resolved for use_device_ptr or is_device_ptr. Could you please point to it?

[clementval]

flang/lib/Parser/openmp-parsers.cpp

207

The error you get seems to be unrelated. Have you tried to apply your patch on a fresh main branch?

[arnamoy10]

Updated changes as per comments.

[clementval]

LGTM. Thanks for updating the patch and sorry for the delay it was not ideal time for me but I'm back at work now.

flang/include/flang/Semantics/symbol.h

ENUM_CLASS(Flag,
       AccCommonBlock, AccThreadPrivate, AccReduction, AccNone, AccPreDetermined,
       // OpenMP data-sharing attribute
       OmpShared, OmpPrivate, OmpLinear, OmpFirstPrivate, OmpLastPrivate,
       // OpenMP data-mapping attribute
       OmpMapTo, OmpMapFrom, OmpMapAlloc, OmpMapRelease, OmpMapDelete,
       // OpenMP data-copying attribute
       OmpCopyIn, OmpCopyPrivate,
       // OpenMP miscellaneous flags
-      OmpCommonBlock, OmpReduction, OmpAligned, OmpAllocate,
+      OmpCommonBlock, OmpReduction, OmpAligned, OmpNontemporal, OmpAllocate,
       OmpDeclarativeAllocateDirective, OmpExecutableAllocateDirective,
       OmpDeclareSimd, OmpDeclareTarget, OmpThreadprivate, OmpDeclareReduction,
       OmpFlushed, OmpCriticalLock, OmpIfSpecified, OmpNone, OmpPreDetermined);
   using Flags = common::EnumSet<Flag, Flag_enumSize>;
 
   const Scope &owner() const { return *owner_; }
   const SourceName &name() const { return name_; }
   Attrs &attrs() { return attrs_; }

flang/lib/Parser/openmp-parsers.cpp

TYPE_PARSER(
     "LINEAR" >> construct<OmpClause>(construct<OmpClause::Linear>(
                     parenthesized(Parser<OmpLinearClause>{}))) ||
     "LINK" >> construct<OmpClause>(construct<OmpClause::Link>(
                   parenthesized(Parser<OmpObjectList>{}))) ||
     "MAP" >> construct<OmpClause>(construct<OmpClause::Map>(
                  parenthesized(Parser<OmpMapClause>{}))) ||
     "MERGEABLE" >> construct<OmpClause>(construct<OmpClause::Mergeable>()) ||
     "NOGROUP" >> construct<OmpClause>(construct<OmpClause::Nogroup>()) ||
+    "NONTEMPORAL" >> construct<OmpClause>(construct<OmpClause::Nontemporal>(
+                         parenthesized(nonemptyList(name)))) ||
     "NOTINBRANCH" >>
         construct<OmpClause>(construct<OmpClause::Notinbranch>()) ||
     "NOWAIT" >> construct<OmpClause>(construct<OmpClause::Nowait>()) ||
     "NUM_TASKS" >> construct<OmpClause>(construct<OmpClause::NumTasks>(
                        parenthesized(scalarIntExpr))) ||
     "NUM_TEAMS" >> construct<OmpClause>(construct<OmpClause::NumTeams>(
                        parenthesized(scalarIntExpr))) ||
     "NUM_THREADS" >> construct<OmpClause>(construct<OmpClause::NumThreads>(

flang/lib/Semantics/resolve-directives.cpp

bool Pre(const parser::OmpClause::Reduction &x) {
     return false;
   }
 
   bool Pre(const parser::OmpAlignedClause &x) {
     const auto &alignedNameList{std::get<std::list<parser::Name>>(x.t)};
     ResolveOmpNameList(alignedNameList, Symbol::Flag::OmpAligned);
     return false;
   }
+
+  bool Pre(const parser::OmpClause::Nontemporal &x) {
+    const auto &nontemporalNameList{x.v};
+    ResolveOmpNameList(nontemporalNameList, Symbol::Flag::OmpNontemporal);
+    return false;
+  }
+
   void Post(const parser::Name &);
 
   // Keep track of labels in the statements that causes jumps to target labels
   void Post(const parser::GotoStmt &gotoStmt) { CheckSourceLabel(gotoStmt.v); }
   void Post(const parser::ComputedGotoStmt &computedGotoStmt) {
     for (auto &label : std::get<std::list<parser::Label>>(computedGotoStmt.t)) {
       CheckSourceLabel(label);
     }

flang/test/Parser/omp-nontemporal-unparse.f90

+! RUN: %flang_fc1 -fdebug-unparse-no-sema -fopenmp %s | FileCheck %s
+
+program omp_simd
+  integer i
+  integer, allocatable :: a(:)
+
+  allocate(a(10))
+
+  !NONTEMPORAL
+  !$omp simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end simd
+end program omp_simd
+!CHECK-LABEL: PROGRAM omp_simd
+
+!NONTEMPORAL
+!CHECK: !$OMP SIMD  NONTEMPORAL(a)

flang/test/Semantics/omp-nontemporal.f90

+! RUN: %S/test_errors.sh %s %t %flang -fopenmp
+! REQUIRES: shell
+! Check OpenMP clause validity for NONTEMPORAL clause
+
+program omp_simd
+  integer i
+  integer, allocatable :: a(:)
+
+  allocate(a(10))
+
+  !$omp simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end simd
+
+  !$omp parallel do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end parallel do simd
+ 
+  !$omp parallel do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end parallel do simd
+
+  !ERROR: NONTEMPORAL clause is not allowed on the DO SIMD directive
+  !$omp do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end do simd
+
+  !$omp taskloop simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end taskloop simd
+
+  !$omp teams
+  !$omp distribute parallel do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end distribute parallel do simd
+  !$omp end teams
+
+  !$omp teams
+  !$omp distribute simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end distribute simd
+  !$omp end teams
+
+  !$omp target parallel do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end target parallel do simd
+
+  !$omp target simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end target simd
+
+  !$omp teams distribute simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end teams distribute simd
+
+  !$omp teams distribute parallel do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end teams distribute parallel do simd
+
+  !$omp target teams distribute parallel do simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end target teams distribute parallel do simd
+
+  !$omp target teams distribute simd nontemporal(a)
+  do i = 1, 10
+    a(i) = i
+  end do
+  !$omp end target teams distribute simd
+
+  
+end program omp_simd

llvm/include/llvm/Frontend/OpenMP/OMP.td

def OMPC_AtomicDefaultMemOrder : Clause<"atomic_default_mem_order"> {
   let clangClass = "OMPAtomicDefaultMemOrderClause";
 }
 def OMPC_Allocate : Clause<"allocate"> {
   let clangClass = "OMPAllocateClause";
   let flangClass = "OmpAllocateClause";
 }
 def OMPC_NonTemporal : Clause<"nontemporal"> {
   let clangClass = "OMPNontemporalClause";
+  let flangClass = "Name";
+  let isValueList = true; 
 }
 
 def OMP_ORDER_concurrent : ClauseVal<"default",2,0> { let isDefault = 1; }
 def OMPC_Order : Clause<"order"> {
   let clangClass = "OMPOrderClause";
   let enumClauseValue = "OrderKind";
   let allowedClauseValues = [
     OMP_ORDER_concurrent