[Flang][AMDGPU] Lower ALLOCATE/DEALLOCATE to runtime calls.

Author: skc7

clang/lib/Driver/ToolChains/Flang.cpp

@@ -432,6 +432,10 @@ void Flang::AddAMDGPUTargetArgs(const ArgList &Args,
         Args.MakeArgString("--amdhsa-code-object-version=" + Val));
   }
 
+  // Force the use of runtime and descriptors for heap allocate/deallocate.
+  CmdArgs.push_back(Args.MakeArgString("-mmlir"));
+  CmdArgs.push_back(Args.MakeArgString("--use-alloc-runtime"));
+
   const ToolChain &TC = getToolChain();
   TC.addClangTargetOptions(Args, CmdArgs, Action::OffloadKind::OFK_OpenMP);
 }

flang/test/Lower/AMDGPU/allocate_deallocate_runtime_calls.f90

@@ -0,0 +1,26 @@
+! RUN: %flang -target amdgcn-- -S -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK-AMDGPU
+! RUN: %flang -target x86_64-- -S -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK-x86_64
+
+subroutine allocate_deallocate()
+  real, allocatable :: x
+
+  allocate(x)
+! CHECK-AMDGPU: call i32 @_FortranAAllocatableAllocate
+! CHECK-x86_64: call ptr @malloc
+
+  deallocate(x)
+! CHECK-AMDGPU: call i32 @_FortranAAllocatableDeallocate
+! CHECK-x86_64: call void @free
+end subroutine
+
+subroutine allocate_deallocate_ptr()
+  integer, pointer :: x
+
+  allocate(x)
+! CHECK-AMDGPU: call i32 @_FortranAPointerAllocate
+! CHECK-x86_64: call i32 @_FortranAPointerAllocate
+
+  deallocate(x)
+! CHECK-AMDGPU: call i32 @_FortranAPointerDeallocate
+! CHECK-x86_64: call i32 @_FortranAPointerDeallocate
+end subroutine