[Flang][OpenMP] Fix to resolve the crash with SIMD aligned clause.

flang/lib/Lower/OpenMP/ClauseProcessor.cpp

@@ -649,8 +649,6 @@ addAlignedClause(lower::AbstractConverter &converter,
   // Do not generate alignment assumption if alignment is less than or equal to
   // 0.
   if (alignment > 0) {
-    // alignment value must be power of 2
-    assert((alignment & (alignment - 1)) == 0 && "alignment is not power of 2");
     auto &objects = std::get<omp::ObjectList>(clause.t);
     if (!objects.empty())
       genObjectList(objects, converter, alignedVars);

flang/test/Lower/OpenMP/simd.f90

@@ -226,6 +226,23 @@ subroutine simdloop_aligned_allocatable()
   end do
 end subroutine
 
+subroutine aligned_non_power_of_two()
+  integer :: i
+  integer, allocatable :: A(:)
+  allocate(A(10))
+!CHECK: %[[A_PTR:.*]] = fir.alloca !fir.box<!fir.heap<!fir.array<?xi32>>> {bindc_name = "a",
+!CHECK-SAME: uniq_name = "_QFaligned_non_power_of_twoEa"}
+!CHECK: %[[A_DECL:.*]]:2 = hlfir.declare %[[A_PTR]] {fortran_attrs = #fir.var_attrs<allocatable>,
+!CHECK-SAME: uniq_name = "_QFaligned_non_power_of_twoEa"} :
+!CHECK-SAME: (!fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>) ->
+!CHECK-SAME: (!fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>, !fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>>)
+!CHECK: omp.simd aligned(%[[A_DECL]]#0 : !fir.ref<!fir.box<!fir.heap<!fir.array<?xi32>>>> -> 257 : i64)
+  !$OMP SIMD ALIGNED(A:257)
+  do i = 1, 10
+    A(i) = i
+  end do
+end subroutine
+
 !CHECK-LABEL: func @_QPsimd_with_nontemporal_clause
 subroutine simd_with_nontemporal_clause(n)
   !CHECK: %[[A_DECL:.*]]:2 = hlfir.declare %{{.*}} {uniq_name = "_QFsimd_with_nontemporal_clauseEa"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)

mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp

@@ -2893,6 +2893,15 @@ convertOmpSimd(Operation &opInst, llvm::IRBuilderBase &builder,
     alignment = builder.getInt64(intAttr.getInt());
     assert(ty->isPointerTy() && "Invalid type for aligned variable");
     assert(alignment && "Invalid alignment value");
+    // Check if the alignment value is not a power of 2. If so, skip emitting
+    // alignment.
+    if (!intAttr.getValue().isPowerOf2()) {
+      emitWarning(simdOp->getLoc())
+          << "The specified alignment value, " << intAttr.getInt()
+          << " is not a power of two and will be ignored";
+      continue;
+    }
+
     auto curInsert = builder.saveIP();
     builder.SetInsertPoint(sourceBlock);
     llvmVal = builder.CreateLoad(ty, llvmVal);

mlir/test/Target/LLVMIR/openmp-simd-aligned.mlir

@@ -58,3 +58,25 @@ llvm.func @_QPsimd_aligned_allocatable() {
   }
   llvm.return
 }
+
+//CHECK-LABEL: define void @_QPsimd_aligned_non_power_of_two() {
+//CHECK:   %[[A_ADDR:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]] }, i64 1, align 8
+//CHECK:   %[[B_ADDR:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]] }, i64 1, align 8
+//CHECK:   %[[LOAD_B:.*]] = load ptr, ptr %[[B_ADDR]], align 8
+//CHECK:   call void @llvm.assume(i1 true) [ "align"(ptr %[[LOAD_B]], i64 64) ]
+//CHECK-NOT:   call void @llvm.assume(i1 true) [ "align"(ptr %{{.*}}, i64 257) ]
+llvm.func @_QPsimd_aligned_non_power_of_two() {
+  %0 = llvm.mlir.constant(1 : i64) : i64
+  %1 = llvm.alloca %0 x !llvm.struct<(ptr, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>)> {bindc_name = "a"} : (i64) -> !llvm.ptr
+  %2 = llvm.alloca %0 x !llvm.struct<(ptr, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>)> {bindc_name = "b"} : (i64) -> !llvm.ptr
+  %3 = llvm.mlir.constant(1 : i32) : i32
+  %4 = llvm.mlir.constant(10 : i32) : i32
+  %5 = llvm.mlir.constant(1 : i32) : i32
+  omp.simd aligned(%1 : !llvm.ptr -> 257 : i64, %2 : !llvm.ptr -> 64 : i64) {
+    omp.loop_nest (%arg0) : i32 = (%3) to (%4) inclusive step (%5) {
+      omp.yield
+    }
+  }
+  llvm.return
+}
+

mlir/test/Target/LLVMIR/openmp-todo.mlir

@@ -129,6 +129,17 @@ llvm.func @simd_linear(%lb : i32, %ub : i32, %step : i32, %x : !llvm.ptr) {
 
 // -----
 
+llvm.func @omp_simd_non_power_of_two_alignment(%lb : i32, %ub : i32, %step : i32, %x : !llvm.ptr) {
+  // expected-warning@below {{The specified alignment value, 257 is not a power of two and will be ignored}}
+  omp.simd aligned(%x : !llvm.ptr -> 257 : i64) {
+    omp.loop_nest (%iv) : i32 = (%lb) to (%ub) step (%step) {
+      omp.yield
+    }
+  }
+  llvm.return
+}
+// -----
+
 omp.declare_reduction @add_f32 : f32
 init {
 ^bb0(%arg: f32):