[llvm] [llvm] Preserve existing calling conv when auto-upgrading nvvm.annota… (PR #125568)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: None (macurtis-amd)

<details>
<summary>Changes</summary>

…tions

Kernels produced by ROCm classic flang may have both nvvm "kernel" annotation and amdgpu_kernel calling convention.

---
Full diff: https://github.com/llvm/llvm-project/pull/125568.diff


2 Files Affected:

- (modified) llvm/lib/IR/AutoUpgrade.cpp (+4-2) 
- (added) llvm/test/CodeGen/AMDGPU/upgrade-nvvm-annotations.ll (+14) 


``````````diff
diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index e886a6012b219ae..c64aec69d9dbb1f 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -5023,8 +5023,10 @@ bool llvm::UpgradeDebugInfo(Module &M) {
 bool static upgradeSingleNVVMAnnotation(GlobalValue *GV, StringRef K,
                                         const Metadata *V) {
   if (K == "kernel") {
-    if (!mdconst::extract<ConstantInt>(V)->isZero())
-      cast<Function>(GV)->setCallingConv(CallingConv::PTX_Kernel);
+    auto *F = cast<Function>(GV);
+    if (!mdconst::extract<ConstantInt>(V)->isZero() &&
+        !F->hasKernelCallingConv())
+      F->setCallingConv(CallingConv::PTX_Kernel);
     return true;
   }
   if (K == "align") {
diff --git a/llvm/test/CodeGen/AMDGPU/upgrade-nvvm-annotations.ll b/llvm/test/CodeGen/AMDGPU/upgrade-nvvm-annotations.ll
new file mode 100644
index 000000000000000..057569f2f1fd6af
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/upgrade-nvvm-annotations.ll
@@ -0,0 +1,14 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -mtriple=amdgcn-amd-amdhsa -O0 -S | FileCheck %s
+
+define amdgpu_kernel void @foo(i32 %a, i32 %b) {
+; CHECK-LABEL: define amdgpu_kernel void @foo(
+; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT:    ret void
+;
+  ret void
+}
+
+!nvvm.annotations = !{!0}
+!0 = !{ptr @foo, !"kernel", i32 1}
+

``````````

</details>


https://github.com/llvm/llvm-project/pull/125568