[flang-commits] [flang] a1bc606 - [Flang][Transform] Modify stack reclaim pass to use allocation address space when generating intrinsics (#96836)

[via flang-commits]

Author: agozillon
Date: 2024-07-03T21:44:50+02:00
New Revision: a1bc606b5fb9a91eb16fc0c012aa785323788c90

URL: https://github.com/llvm/llvm-project/commit/a1bc606b5fb9a91eb16fc0c012aa785323788c90
DIFF: https://github.com/llvm/llvm-project/commit/a1bc606b5fb9a91eb16fc0c012aa785323788c90.diff

LOG: [Flang][Transform] Modify stack reclaim pass to use allocation address space when generating intrinsics (#96836)

This PR aims to factor in the allocation address space provided by an
architectures data layout when generating the intrinsic instructions,
this allows them to be lowered later with the address spaces in tow.
This aligns the intrinsic creation with the LLVM IRBuilder's
https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/IR/IRBuilder.h#L1053

This is also necessary for the below example to compile for OpenMP AMD
GPU and not ICE the compiler in ISEL as AMD's stackrestore and stacksave
are expected to have the appropriate allocation address space for AMD
GPU.

program main
    integer(4), allocatable :: test
    allocate(test)

!$omp target map(tofrom:test)
    do i = 1, 10
      test = test + 50
    end do
!$omp end target

  deallocate(test)
end program

The PR also fixes the issue I opened a while ago which hits the same
error when compiling for AMDGPU:
https://github.com/llvm/llvm-project/issues/82368

Although, you have to have the appropriate GPU LIBC and Fortran offload
runtime (both compiled for AMDGPU) added to the linker for the command
or it will reach another ISEL error and ICE weirdly. But with the
pre-requisites it works fine with this PR.

Added: 
    

Modified: 
    flang/lib/Optimizer/Transforms/StackReclaim.cpp
    flang/test/Transforms/stack-reclaime.fir

Removed: 
    


################################################################################
diff  --git a/flang/lib/Optimizer/Transforms/StackReclaim.cpp b/flang/lib/Optimizer/Transforms/StackReclaim.cpp
index e5e0e4eab8298..8a60a9e64f704 100644
--- a/flang/lib/Optimizer/Transforms/StackReclaim.cpp
+++ b/flang/lib/Optimizer/Transforms/StackReclaim.cpp
@@ -31,11 +31,23 @@ class StackReclaimPass : public fir::impl::StackReclaimBase<StackReclaimPass> {
 };
 } // namespace
 
+uint64_t getAllocaAddressSpace(Operation *op) {
+  mlir::ModuleOp module = mlir::dyn_cast_or_null<mlir::ModuleOp>(op);
+  if (!module)
+    module = op->getParentOfType<mlir::ModuleOp>();
+
+  if (mlir::Attribute addrSpace =
+          mlir::DataLayout(module).getAllocaMemorySpace())
+    return llvm::cast<mlir::IntegerAttr>(addrSpace).getUInt();
+  return 0;
+}
+
 void StackReclaimPass::runOnOperation() {
   auto *op = getOperation();
   auto *context = &getContext();
   mlir::OpBuilder builder(context);
-  mlir::Type voidPtr = mlir::LLVM::LLVMPointerType::get(context);
+  mlir::Type voidPtr =
+      mlir::LLVM::LLVMPointerType::get(context, getAllocaAddressSpace(op));
 
   op->walk([&](fir::DoLoopOp loopOp) {
     mlir::Location loc = loopOp.getLoc();

diff  --git a/flang/test/Transforms/stack-reclaime.fir b/flang/test/Transforms/stack-reclaime.fir
index b53cc96035751..96416df8b2013 100644
--- a/flang/test/Transforms/stack-reclaime.fir
+++ b/flang/test/Transforms/stack-reclaime.fir
@@ -12,3 +12,20 @@ func.func @alloca_in_loop(%lb : index, %ub : index, %step : index, %b : i1, %add
 // CHECK: %[[STACKPTR:.*]] = llvm.intr.stacksave : !llvm.ptr
 // CHECK: %{{.*}} = fir.alloca !fir.box<!fir.heap<!fir.char<1,?>>>
 // CHECK: llvm.intr.stackrestore %0 : !llvm.ptr
+
+// -----
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<#dlti.dl_entry<"dlti.alloca_memory_space", 5 : ui64>>} {
+  func.func @stack_restore_save_alloca_address(%lb : index, %ub : index, %step : index, %b : i1, %addr : !fir.ref<index>) {
+    fir.do_loop %iv = %lb to %ub step %step unordered {
+      %0 = fir.alloca !fir.box<!fir.heap<!fir.char<1,?>>>
+    }
+    return
+  }
+}
+
+// CHECK-LABEL: func.func @stack_restore_save_alloca_address
+// CHECK: fir.do_loop
+// CHECK: %[[STACKPTR:.*]] = llvm.intr.stacksave : !llvm.ptr<5>
+// CHECK: %{{.*}} = fir.alloca !fir.box<!fir.heap<!fir.char<1,?>>>
+// CHECK: llvm.intr.stackrestore %0 : !llvm.ptr<5>