[PATCH] D135674: [NVPTX] Fix pointer argument declaration for --nvptx-short-ptr

[Andrew Savonichev via Phabricator via llvm-commits]

asavonic created this revision.
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When --nvptx-short-ptr is set, local pointers are 32-bit on nvptx64 target.

Before this patch, arguments for a function declaration were always
emitted as b64 regardless of their address space, but they were correctly 
set as b32 for the corresponding call instruction:

  .extern .func test
  (
   .param .b64 test_param_0
  )
  [...]
   .param .b32 param0;
   st.param.b32 [param0+0], %r1;
   call.uni test, (param0);

This is not supported:

  ptxas: Type of argument does not match formal parameter
  'test_param_0'

Now short pointers in a function declaration are emitted as b32 if
--nvptx-short-ptr is set.

This patch fixes the bug found in https://reviews.llvm.org/D127668#3587241.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D135674

Files:
  llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
  llvm/test/CodeGen/NVPTX/short-ptr.ll


Index: llvm/test/CodeGen/NVPTX/short-ptr.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/NVPTX/short-ptr.ll
@@ -0,0 +1,34 @@
+; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 | FileCheck %s --check-prefix CHECK-DEFAULT
+; RUN: llc < %s -march=nvptx -mcpu=sm_20 | FileCheck %s --check-prefix CHECK-DEFAULT-32
+; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -nvptx-short-ptr | FileCheck %s --check-prefixes CHECK-SHORT-LOCAL
+
+; RUN: %if ptxas %{ llc < %s -march=nvptx -mcpu=sm_20 | %ptxas-verify %}
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 | %ptxas-verify %}
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -nvptx-short-ptr | %ptxas-verify %}
+
+declare void @use(i8 %arg);
+
+; CHECK-DEFAULT: .param .b64 test1_param_0
+; CHECK-DEFAULT-32: .param .b32 test1_param_0
+; CHECK-SHORT-LOCAL: .param .b32 test1_param_0
+define void @test1(i8 addrspace(5)* %local) {
+  ; CHECK-DEFAULT: ld.param.u64 %rd{{.*}}, [test1_param_0];
+  ; CHECK-DEFAULT-32:  ld.param.u32 %r{{.*}}, [test1_param_0];
+  ; CHECK-SHORT-LOCAL: ld.param.u32 %r{{.*}}, [test1_param_0];
+  %v = load i8, i8 addrspace(5)* %local
+  call void @use(i8 %v)
+  ret void
+}
+
+define void @test2() {
+  %v = alloca i8
+  %cast = addrspacecast i8* %v to i8 addrspace(5)*
+  ; CHECK-DEFAULT: .param .b64 param0;
+  ; CHECK-DEFAULT: st.param.b64
+  ; CHECK-DEFAULT-32: .param .b32 param0;
+  ; CHECK-DEFAULT-32: st.param.b32
+  ; CHECK-SHORT-LOCAL: .param .b32 param0;
+  ; CHECK-SHORT-LOCAL: st.param.b32
+  call void @test1(i8 addrspace(5)* %cast)
+  ret void
+}
Index: llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
===================================================================
--- llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -1457,7 +1457,6 @@
   bool isKernelFunc = isKernelFunction(*F);
   bool isABI = (STI.getSmVersion() >= 20);
   bool hasImageHandles = STI.hasImageHandles();
-  MVT thePointerTy = TLI->getPointerTy(DL);
 
   if (F->arg_empty()) {
     O << "()\n";
@@ -1530,10 +1529,16 @@
       }
       // Just a scalar
       auto *PTy = dyn_cast<PointerType>(Ty);
+      unsigned PTySizeInBits = 0;
+      if (PTy) {
+        PTySizeInBits =
+            TLI->getPointerTy(DL, PTy->getAddressSpace()).getSizeInBits();
+      }
+
       if (isKernelFunc) {
         if (PTy) {
           // Special handling for pointer arguments to kernel
-          O << "\t.param .u" << thePointerTy.getSizeInBits() << " ";
+          O << "\t.param .u" << PTySizeInBits << " ";
 
           if (static_cast<NVPTXTargetMachine &>(TM).getDrvInterface() !=
               NVPTX::CUDA) {
@@ -1577,7 +1582,7 @@
         sz = cast<IntegerType>(Ty)->getBitWidth();
         sz = promoteScalarArgumentSize(sz);
       } else if (isa<PointerType>(Ty))
-        sz = thePointerTy.getSizeInBits();
+        sz = PTySizeInBits;
       else if (Ty->isHalfTy())
         // PTX ABI requires all scalar parameters to be at least 32
         // bits in size.  fp16 normally uses .b16 as its storage type


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