[Mlir-commits] [flang] [mlir] [flang][OpenMP] Ignore DECLARE_SIMD and warn about missing implementa… (PR #232712)

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Fri Oct 16 05:16:01 PDT 2026


llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-semantics

Author: Krzysztof Parzyszek (kparzysz)

<details>
<summary>Changes</summary>

…tion

DECLARE_SIMD is a hint to the compiler and ignoring it is technically speaking a conforming implementation (although obviously not desirable). Do not abort compilation when DECLARE_SIMD is encountered, but emit a warning that it's currently ignored.

---
Full diff: https://github.com/llvm/llvm-project/pull/232712.diff


14 Files Affected:

- (modified) flang/lib/Semantics/check-omp-structure.cpp (+4) 
- (modified) flang/test/Semantics/OpenMP/cray-pointer-usage.f90 (+1) 
- (modified) flang/test/Semantics/OpenMP/declarative-directive01.f90 (+2) 
- (modified) flang/test/Semantics/OpenMP/declare-simd-empty.f90 (+2) 
- (modified) flang/test/Semantics/OpenMP/declare-simd-interface-body.f90 (+5-1) 
- (modified) flang/test/Semantics/OpenMP/declare-simd-scope.f90 (+12) 
- (modified) flang/test/Semantics/OpenMP/declare-simd-uniform.f90 (+2) 
- (modified) flang/test/Semantics/OpenMP/declare-simd.f90 (+6-1) 
- (modified) flang/test/Semantics/OpenMP/future-directive-spellings.f90 (+1) 
- (modified) flang/test/Semantics/OpenMP/linear-clause01.f90 (+9) 
- (modified) flang/test/Semantics/OpenMP/linear-clause02.f90 (+3) 
- (modified) flang/test/Semantics/OpenMP/linear-clause03.f90 (+1) 
- (modified) flang/test/Semantics/OpenMP/simd-linear-array.f90 (+1) 
- (modified) mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp (+7) 


``````````diff
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index 07c9a5222883c..e5b0433ef0220 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -2201,6 +2201,10 @@ void OmpStructureChecker::Enter(const parser::OmpDeclareSimdDirective &x) {
 
   llvm::omp::Version version{context_.langOptions().getOpenMPVersion()};
 
+  context_.Say(dirName.source,
+      "%s directive is not implemented yet and will be ignored"_warn_en_US,
+      GetUpperName(dirName.v, version));
+
   const Scope &containingScope = context_.FindScope(dirName.source);
   const Scope &progUnitScope = GetProgramUnitContaining(containingScope);
 
diff --git a/flang/test/Semantics/OpenMP/cray-pointer-usage.f90 b/flang/test/Semantics/OpenMP/cray-pointer-usage.f90
index 025d339ec8174..8a1b1f0ec90ec 100644
--- a/flang/test/Semantics/OpenMP/cray-pointer-usage.f90
+++ b/flang/test/Semantics/OpenMP/cray-pointer-usage.f90
@@ -4,6 +4,7 @@ subroutine test_cray_pointer_usage
   integer :: i
   real(8) :: var(*), pointee(2)
   pointer(ivar, var)
+  ! WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   ! ERROR: Cray Pointee 'var' may not appear in LINEAR clause
   ! ERROR: List item 'var' in LINEAR clause must be a scalar variable
   ! ERROR: The list item 'var' specified without the REF 'linear-modifier' must be of INTEGER type
diff --git a/flang/test/Semantics/OpenMP/declarative-directive01.f90 b/flang/test/Semantics/OpenMP/declarative-directive01.f90
index 9e0612b5c8b53..d1ecbf1844944 100644
--- a/flang/test/Semantics/OpenMP/declarative-directive01.f90
+++ b/flang/test/Semantics/OpenMP/declarative-directive01.f90
@@ -21,6 +21,7 @@ end subroutine requires_2
 
 subroutine declare_simd_1(a, b)
   real(8), intent(inout) :: a, b
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !ERROR: 'a' in ALIGNED clause must be of type C_PTR, POINTER or ALLOCATABLE
   !$omp declare simd(declare_simd_1) aligned(a)
   a = 3.14 + b
@@ -38,6 +39,7 @@ end module m1
 subroutine declare_simd_2
   use m1
   procedure (sub) sub1
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !ERROR: INBRANCH and NOTINBRANCH clauses are mutually exclusive and may not appear on the same DECLARE SIMD directive
   !$omp declare simd(sub1) inbranch notinbranch
   procedure (sub), pointer::p
diff --git a/flang/test/Semantics/OpenMP/declare-simd-empty.f90 b/flang/test/Semantics/OpenMP/declare-simd-empty.f90
index 11aaa8ffc54f0..15e1a61ba08f0 100644
--- a/flang/test/Semantics/OpenMP/declare-simd-empty.f90
+++ b/flang/test/Semantics/OpenMP/declare-simd-empty.f90
@@ -3,6 +3,8 @@
 
 ! The directive is in the specification part of a main program, which is not a
 ! subroutine subprogram, function subprogram, or interface body.
+
+!WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
 !$omp declare simd
 integer :: x
diff --git a/flang/test/Semantics/OpenMP/declare-simd-interface-body.f90 b/flang/test/Semantics/OpenMP/declare-simd-interface-body.f90
index 624afa8852f2e..7a8553be41219 100644
--- a/flang/test/Semantics/OpenMP/declare-simd-interface-body.f90
+++ b/flang/test/Semantics/OpenMP/declare-simd-interface-body.f90
@@ -6,12 +6,14 @@
 
 interface
   subroutine add2(i)
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !WARNING: 'DECLARE SIMD' directive in an interface body has no effect [-Wopenmp-usage]
   !$omp declare simd(add2) linear(i:1)
     integer :: i
   end subroutine
 
   subroutine add3(i)
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !WARNING: 'DECLARE SIMD' directive in an interface body has no effect [-Wopenmp-usage]
   !$omp declare simd
     integer :: i
@@ -20,8 +22,10 @@ subroutine add3(i)
 
 contains
 
-! A DECLARE SIMD in an actual definition is fine and must not warn.
+! A DECLARE SIMD in an actual definition is fine and must not warn about
+! its effect.
 subroutine sub(i)
+!WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
 !$omp declare simd(sub) linear(i:1)
   integer :: i
   i = i + 1
diff --git a/flang/test/Semantics/OpenMP/declare-simd-scope.f90 b/flang/test/Semantics/OpenMP/declare-simd-scope.f90
index 64870cd79f42c..a53ffe7f31100 100644
--- a/flang/test/Semantics/OpenMP/declare-simd-scope.f90
+++ b/flang/test/Semantics/OpenMP/declare-simd-scope.f90
@@ -8,9 +8,11 @@
 module m
   procedure() :: ext
 
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
   !$omp declare simd
 
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
   !$omp declare_simd(ext)
 
@@ -19,6 +21,7 @@ module m
   ! Ok: module subprogram.
   subroutine mod_sub(i)
     integer :: i
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
     !$omp declare simd(mod_sub) linear(i:1)
     i = i + 1
   end subroutine
@@ -26,12 +29,14 @@ subroutine mod_sub(i)
   ! Ok: module function.
   integer function mod_fun(i)
     integer :: i
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
     !$omp declare_simd
     mod_fun = i
   end function
 end module
 
 submodule (m) sm
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
   !$omp declare simd
 end submodule
@@ -39,12 +44,14 @@ integer function mod_fun(i)
 block data bd
   integer :: x
   common /blk/ x
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
   !$omp declare simd
   data x /0/
 end block data
 
 program main
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
   !$omp declare simd
 end program
@@ -54,6 +61,7 @@ program main
 subroutine in_block(i)
   integer :: i
   block
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
     !$omp declare simd
     i = i + 1
@@ -63,6 +71,7 @@ subroutine in_block(i)
 ! Ok: external subroutine.
 subroutine ext_sub(i)
   integer :: i
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
   !$omp declare simd(ext_sub) linear(i:1)
   i = i + 1
 end subroutine
@@ -70,12 +79,14 @@ subroutine ext_sub(i)
 ! Ok: external function, with an internal subprogram.
 integer function ext_fun(i)
   integer :: i
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
   !$omp declare simd(ext_fun)
   ext_fun = inner(i)
 contains
   ! Ok: internal subprogram.
   integer function inner(j)
     integer :: j
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
     !$omp declare simd(inner) linear(j:1)
     inner = j
   end function
@@ -85,6 +96,7 @@ integer function inner(j)
 subroutine has_interface
   interface
     subroutine iface_sub(i)
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !WARNING: 'DECLARE SIMD' directive in an interface body has no effect [-Wopenmp-usage]
       !$omp declare simd(iface_sub) linear(i:1)
       integer :: i
diff --git a/flang/test/Semantics/OpenMP/declare-simd-uniform.f90 b/flang/test/Semantics/OpenMP/declare-simd-uniform.f90
index 1ca18a98976e3..f63892c8fb996 100644
--- a/flang/test/Semantics/OpenMP/declare-simd-uniform.f90
+++ b/flang/test/Semantics/OpenMP/declare-simd-uniform.f90
@@ -3,6 +3,7 @@
 ! Test declare simd with uniform clause
 
 function add2(a,b,i,fact,alc) result(c)
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !$omp declare simd(add2) uniform(a,b,fact)
   integer :: i
   integer,pointer::alc
@@ -27,6 +28,7 @@ function bad_uniform(a,b,i) result(c)
   double precision :: a(*), b(*), c
   integer :: i
   double precision :: local
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !ERROR: Variable 'local' in UNIFORM clause must be a dummy argument of the enclosing procedure
   !$omp declare simd(bad_uniform) uniform(a,local)
   c = a(i) + b(i) + local
diff --git a/flang/test/Semantics/OpenMP/declare-simd.f90 b/flang/test/Semantics/OpenMP/declare-simd.f90
index 2e98f79dbe73b..45c049ddf6aff 100644
--- a/flang/test/Semantics/OpenMP/declare-simd.f90
+++ b/flang/test/Semantics/OpenMP/declare-simd.f90
@@ -5,28 +5,33 @@ module m
 integer :: x
 
 ! A DECLARE_SIMD directive cannot appear in the specification part of a module.
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive must appear in the specification part of a subroutine subprogram, function subprogram, or interface body
 !$omp declare_simd(f00)
 
 contains
 
 subroutine f00
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: The name 'x' should refer to a procedure
 !$omp declare_simd(x)
 end
 
 subroutine f01
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: DECLARE_SIMD directive should have at most one argument
 !$omp declare_simd(f00, f01)
 end
 
 subroutine f02
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !ERROR: The argument to the DECLARE_SIMD directive should be a procedure name
 !$omp declare_simd(v : integer)
 end
 
 integer function f03
-!Ok, expect no diagnostics
+!Ok, expect no errors
+!WARNING: DECLARE_SIMD directive is not implemented yet and will be ignored
 !$omp declare_simd(f03)
 end
 
diff --git a/flang/test/Semantics/OpenMP/future-directive-spellings.f90 b/flang/test/Semantics/OpenMP/future-directive-spellings.f90
index b7705ddd95c4a..8445bef52ebb1 100644
--- a/flang/test/Semantics/OpenMP/future-directive-spellings.f90
+++ b/flang/test/Semantics/OpenMP/future-directive-spellings.f90
@@ -41,6 +41,7 @@ subroutine f02
 end
 
 subroutine f03
+!WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
 !WARNING: Directive spelling 'DECLARE_SIMD' is introduced in a later OpenMP version, try -fopenmp-version=60
   !$omp declare_simd
 end
diff --git a/flang/test/Semantics/OpenMP/linear-clause01.f90 b/flang/test/Semantics/OpenMP/linear-clause01.f90
index dd10ceaf669ff..8ebc5830cbfe8 100644
--- a/flang/test/Semantics/OpenMP/linear-clause01.f90
+++ b/flang/test/Semantics/OpenMP/linear-clause01.f90
@@ -21,11 +21,13 @@ subroutine linear_clause_02(arg_01, arg_02)
     !ERROR: The list item 'arg_01' specified without the REF 'linear-modifier' must be of INTEGER type
     !ERROR: List item 'arg_01' in LINEAR clause must be a scalar variable
     !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !$omp declare simd linear(val(arg_01))
     real, intent(in) :: arg_01(:)
 
     !ERROR: If the `linear-modifier` is REF or UVAL, the list item 'arg_02' must be a dummy argument without the VALUE attribute
     !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !$omp declare simd linear(uval(arg_02))
     integer, value, intent(in) :: arg_02
 
@@ -33,6 +35,7 @@ subroutine linear_clause_02(arg_01, arg_02)
     !ERROR: The list item `var` must be a dummy argument
     !ERROR: The list item `var` in a LINEAR clause must not be Cray Pointer or a variable with POINTER attribute
     !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !$omp declare simd linear(uval(var))
     integer, pointer :: var
 end subroutine linear_clause_02
@@ -43,13 +46,16 @@ subroutine linear_clause_03(arg)
     !ERROR: List item 'arg' present at multiple LINEAR clauses
     !ERROR: 'arg' appears in more than one data-sharing clause on the same OpenMP directive
     !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !$omp declare simd linear(ref(arg)) linear(arg)
 
     integer :: i
     common /cc/ i
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !ERROR: The list item `i` must be a dummy argument
     !$omp declare simd linear(i)
 
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !ERROR: 'cc' is a common block name and must not appear in a LINEAR clause
     !ERROR: The list item `i` must be a dummy argument
     !$omp declare simd linear(/cc/)
@@ -71,6 +77,7 @@ end subroutine linear_clause_04
 ! Case 5
 subroutine linear_clause_05(x)
     integer :: x(:)
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !ERROR: The list item `x` specified with the REF 'linear-modifier' must not be a polymorphic variable, an assumed-shape array, or a variable with the `ALLOCATABLE` attribute
     !$omp declare simd linear(x : ref)
 end subroutine linear_clause_05
@@ -78,6 +85,7 @@ end subroutine linear_clause_05
 ! Case 6
 subroutine linear_clause_06(x)
     integer, allocatable :: x(:)
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !ERROR: The list item `x` specified with the REF 'linear-modifier' must not be a polymorphic variable, an assumed-shape array, or a variable with the `ALLOCATABLE` attribute
     !$omp declare simd linear(x : ref)
 end subroutine linear_clause_06
@@ -85,6 +93,7 @@ end subroutine linear_clause_06
 ! Case 7
 subroutine linear_clause_07(x)
     type(*) :: x(:)
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !ERROR: The list item `x` specified with the REF 'linear-modifier' must not be a polymorphic variable, an assumed-shape array, or a variable with the `ALLOCATABLE` attribute
     !$omp declare simd linear(x : ref)
 end subroutine linear_clause_07
diff --git a/flang/test/Semantics/OpenMP/linear-clause02.f90 b/flang/test/Semantics/OpenMP/linear-clause02.f90
index e6eedbcae7c92..2ac816d1ff3ec 100644
--- a/flang/test/Semantics/OpenMP/linear-clause02.f90
+++ b/flang/test/Semantics/OpenMP/linear-clause02.f90
@@ -3,18 +3,21 @@
 subroutine f00(x)
   integer :: x
   !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !$omp declare simd linear(uval(x))
 end
 
 subroutine f01(x)
   integer :: x
   !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !ERROR: An exclusive 'step-simple-modifier' modifier cannot be specified together with a modifier of a different type
   !$omp declare simd linear(uval(x) : 2)
 end
 
 subroutine f02(x)
   integer :: x
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !ERROR: 'step-simple-modifier' modifier cannot occur multiple times
   !$omp declare simd linear(x : 2, 2)
 end
diff --git a/flang/test/Semantics/OpenMP/linear-clause03.f90 b/flang/test/Semantics/OpenMP/linear-clause03.f90
index dafc2e929801c..0866e38ba1c04 100644
--- a/flang/test/Semantics/OpenMP/linear-clause03.f90
+++ b/flang/test/Semantics/OpenMP/linear-clause03.f90
@@ -6,6 +6,7 @@ module m
   subroutine f(x, y)
     integer :: x
     integer :: y
+    !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
     !WARNING: 'DECLARE SIMD' directive in an interface body has no effect [-Wopenmp-usage]
     !$omp declare simd(f) linear(ref(x) : 1) linear(uval(y))
   end
diff --git a/flang/test/Semantics/OpenMP/simd-linear-array.f90 b/flang/test/Semantics/OpenMP/simd-linear-array.f90
index cfebace48ee59..58582b14af67d 100644
--- a/flang/test/Semantics/OpenMP/simd-linear-array.f90
+++ b/flang/test/Semantics/OpenMP/simd-linear-array.f90
@@ -76,6 +76,7 @@ subroutine test_declare_simd_ref_array_valid(arr)
   integer, intent(in) :: arr(10)
   
   !WARNING: The 'modifier(<list>)' syntax is deprecated in OpenMP v5.2, use '<list> : modifier' instead
+  !WARNING: DECLARE SIMD directive is not implemented yet and will be ignored
   !$omp declare simd linear(ref(arr))
   ! No error expected - REF modifier allows arrays
 end subroutine
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index 935aa3232fa2e..1f3d32fd0b993 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -10945,6 +10945,13 @@ LogicalResult OpenMPDialectLLVMIRTranslationInterface::convertOperation(
           .Case([&](omp::GroupprivateOp) {
             return convertOmpGroupprivate(*op, builder, moduleTranslation);
           })
+          .Case([&](omp::DeclareSimdOp) {
+            // TODO: Implement.
+            // DECLARE_SIMD can be ignored. There is warning emitted in
+            // semantic checks about the current situation, but not having an
+            // implementation should not prevent compilation.
+            return success();
+          })
           .Default([&](Operation *inst) {
             return inst->emitError()
                    << "not yet implemented: " << inst->getName();

``````````

</details>


https://github.com/llvm/llvm-project/pull/232712


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