[libc-commits] [libcxx] [compiler-rt] [clang] [libc] [clang-tools-extra] [flang] [llvm] [clang][AMDGPU] fix the return type for ballot (PR #73906)

[Sameer Sahasrabuddhe via libc-commits]

https://github.com/ssahasra updated https://github.com/llvm/llvm-project/pull/73906

>From 8ecb6310a4912de50628cf3db5ff8488fa919bb1 Mon Sep 17 00:00:00 2001
From: Sameer Sahasrabuddhe <sameer.sahasrabuddhe at amd.com>
Date: Fri, 1 Dec 2023 14:24:30 +0530
Subject: [PATCH 1/2] [clang][AMDGPU] precommit test for ballot on Windows

The Clang declaration of the wave-64 builtin uses "UL" as the return type, which
is interpreted as a 32-bit unsigned integer on Windows. This emits an incorrect
LLVM declaration with i32 return type instead of i64. The clang declaration
needs to be fixed to use "WU" instead.
---
 clang/test/CodeGenHIP/ballot.cpp | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 clang/test/CodeGenHIP/ballot.cpp

diff --git a/clang/test/CodeGenHIP/ballot.cpp b/clang/test/CodeGenHIP/ballot.cpp
new file mode 100644
index 0000000000000..6e1cbbdfc7af1
--- /dev/null
+++ b/clang/test/CodeGenHIP/ballot.cpp
@@ -0,0 +1,27 @@
+// REQUIRES: amdgpu-registered-target
+// XFAIL: *
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -aux-triple x86_64-pc-windows-msvc -target-cpu gfx900 -x hip -emit-llvm -fcuda-is-device -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -aux-triple x86_64-pc-windows-msvc -target-cpu gfx900 -x hip -S -fcuda-is-device -o - %s | FileCheck %s --check-prefix=GFX9
+
+// Unlike OpenCL, HIP depends on the C++ interpration of "unsigned long", which
+// is 64 bits long on Linux and 32 bits long on Windows. The return type of the
+// ballot intrinsic needs to be a 64 bit integer on both platforms. This test
+// cross-compiles to Windows to confirm that the return type is indeed 64 bits
+// on Windows.
+
+// FIXME: The Clang declaration of the wave-64 builtin uses "UL" as the return
+// type, which is interpreted as a 32-bit unsigned integer on Windows. This
+// emits an incorrect LLVM declaration with i32 return type instead of i64. The
+// clang declaration needs to be fixed to use "WU" instead.
+
+// CHECK-LABEL: @_Z3fooi
+// CHECK: call i64 @llvm.amdgcn.ballot.i64
+
+// GFX9-LABEL: _Z3fooi:
+// GFX9: v_cmp_ne_u32_e64
+
+#define __device__ __attribute__((device))
+
+__device__ unsigned long long foo(int p) {
+  return __builtin_amdgcn_ballot_w64(p);
+}

>From bfcff343a601923da554cafda26568a445fc39b0 Mon Sep 17 00:00:00 2001
From: Sameer Sahasrabuddhe <sameer.sahasrabuddhe at amd.com>
Date: Thu, 30 Nov 2023 12:14:38 +0530
Subject: [PATCH 2/2] [clang][AMDGPU] fix the return type for ballot

In the builtins declaration, "ULi" is a 32-bit integer on Windows. Use "WUi"
instead to ensure a 64-bit integer on all platforms.
---
 clang/include/clang/Basic/BuiltinsAMDGPU.def | 4 ++--
 clang/test/CodeGenHIP/ballot.cpp             | 6 ------
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/clang/include/clang/Basic/BuiltinsAMDGPU.def b/clang/include/clang/Basic/BuiltinsAMDGPU.def
index a19c8bd5f219e..8b59b3790d7bc 100644
--- a/clang/include/clang/Basic/BuiltinsAMDGPU.def
+++ b/clang/include/clang/Basic/BuiltinsAMDGPU.def
@@ -150,8 +150,8 @@ BUILTIN(__builtin_amdgcn_mqsad_u32_u8, "V4UiWUiUiV4Ui", "nc")
 // Ballot builtins.
 //===----------------------------------------------------------------------===//
 
-TARGET_BUILTIN(__builtin_amdgcn_ballot_w32, "Uib", "nc", "wavefrontsize32")
-TARGET_BUILTIN(__builtin_amdgcn_ballot_w64, "LUib", "nc", "wavefrontsize64")
+TARGET_BUILTIN(__builtin_amdgcn_ballot_w32, "ZUib", "nc", "wavefrontsize32")
+TARGET_BUILTIN(__builtin_amdgcn_ballot_w64, "WUib", "nc", "wavefrontsize64")
 
 // Deprecated intrinsics in favor of __builtin_amdgn_ballot_{w32|w64}
 BUILTIN(__builtin_amdgcn_uicmp, "WUiUiUiIi", "nc")
diff --git a/clang/test/CodeGenHIP/ballot.cpp b/clang/test/CodeGenHIP/ballot.cpp
index 6e1cbbdfc7af1..a1c23e2136c71 100644
--- a/clang/test/CodeGenHIP/ballot.cpp
+++ b/clang/test/CodeGenHIP/ballot.cpp
@@ -1,5 +1,4 @@
 // REQUIRES: amdgpu-registered-target
-// XFAIL: *
 // RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -aux-triple x86_64-pc-windows-msvc -target-cpu gfx900 -x hip -emit-llvm -fcuda-is-device -o - %s | FileCheck %s
 // RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -aux-triple x86_64-pc-windows-msvc -target-cpu gfx900 -x hip -S -fcuda-is-device -o - %s | FileCheck %s --check-prefix=GFX9
 
@@ -9,11 +8,6 @@
 // cross-compiles to Windows to confirm that the return type is indeed 64 bits
 // on Windows.
 
-// FIXME: The Clang declaration of the wave-64 builtin uses "UL" as the return
-// type, which is interpreted as a 32-bit unsigned integer on Windows. This
-// emits an incorrect LLVM declaration with i32 return type instead of i64. The
-// clang declaration needs to be fixed to use "WU" instead.
-
 // CHECK-LABEL: @_Z3fooi
 // CHECK: call i64 @llvm.amdgcn.ballot.i64