[NVPTX] Annotate CUDA kernel pointer arguments with .ptr .space .align attributes.

llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp

@@ -1588,12 +1588,22 @@ void NVPTXAsmPrinter::emitFunctionParamList(const Function *F, raw_ostream &O) {
 
       if (isKernelFunc) {
         if (PTy) {
-          // Special handling for pointer arguments to kernel
           O << "\t.param .u" << PTySizeInBits << " ";
 
-          if (static_cast<NVPTXTargetMachine &>(TM).getDrvInterface() !=
+          int addrSpace = PTy->getAddressSpace();
+          if (static_cast<NVPTXTargetMachine &>(TM).getDrvInterface() ==
               NVPTX::CUDA) {
-            int addrSpace = PTy->getAddressSpace();
+            // Special handling for pointer arguments to kernel
+            // CUDA kernels assume that pointers are in global address space
+            // See:
+            // https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#parameter-state-space
+            assert(addrSpace == 0 && "Invalid address space");
+            O << ".ptr .global ";
+            if (I->getParamAlign().valueOrOne() != 1) {
+              Align ParamAlign = I->getParamAlign().value();
+              O << ".align " << ParamAlign.value() << " ";
+            }
+          } else {
             switch (addrSpace) {
             default:
               O << ".ptr ";

llvm/test/CodeGen/NVPTX/kernel-param-align.ll

@@ -0,0 +1,34 @@
+; RUN: llc < %s -march=nvptx64 -mcpu=sm_72 2>&1 | FileCheck %s
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_72 | %ptxas-verify %}
+
+%struct.Large = type { [16 x double] }
+
+; CHECK: .param .u64 .ptr .global .align 16 func_align_param_0,
+; CHECK: .param .u64 .ptr .global func_align_param_1,
+; CHECK: .param .u32 .ptr .global func_align_param_2
+define void @func_align(ptr nocapture readonly align 16 %input, ptr addrspace(3) nocapture %out, i32 %n) {
+entry:
+  %0 = addrspacecast ptr %out to ptr addrspace(1)
+  %1 = addrspacecast ptr %input to ptr addrspace(1)
+  %getElem = getelementptr inbounds %struct.Large, ptr addrspace(1) %1, i64 0, i32 0, i64 5
+  %tmp2 = load i32, ptr addrspace(1) %getElem, align 8
+  store i32 %tmp2, ptr addrspace(1) %0, align 4
+  ret void
+}
+
+; CHECK: .param .ptr .global .u64 func_param_0,
+; CHECK: .param .ptr .global .u64 func_param_1,
+; CHECK: .param .u32 func_param_2
+define void @func(ptr nocapture readonly %input, ptr nocapture %out, i32 %n) {
+entry:
+  %0 = addrspacecast ptr %out to ptr addrspace(1)
+  %1 = addrspacecast ptr %input to ptr addrspace(1)
+  %getElem = getelementptr inbounds %struct.Large, ptr addrspace(1) %1, i64 0, i32 0, i64 5
+  %tmp2 = load i32, ptr addrspace(1) %getElem, align 8
+  store i32 %tmp2, ptr addrspace(1) %0, align 4
+  ret void
+}
+
+!nvvm.annotations = !{!0, !1}
+!0 = !{ptr @func_align, !"kernel", i32 1}
+!1 = !{ptr @func, !"kernel", i32 1}