[clang] 5ed5b7b - [clang][NVPTX] exclude feature attributes from target-features (#215451)

[via cfe-commits]

Author: Alex MacLean
Date: 2026-08-21T20:08:44-07:00
New Revision: 5ed5b7b91cb53f898615aa6cbbee6f22822bb8b6

URL: https://github.com/llvm/llvm-project/commit/5ed5b7b91cb53f898615aa6cbbee6f22822bb8b6
DIFF: https://github.com/llvm/llvm-project/commit/5ed5b7b91cb53f898615aa6cbbee6f22822bb8b6.diff

LOG: [clang][NVPTX] exclude feature attributes from target-features (#215451)

Added: 
    

Modified: 
    clang/lib/Basic/Targets/NVPTX.cpp
    clang/lib/CodeGen/CodeGenModule.cpp
    clang/test/CodeGen/nvptx_attributes.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Basic/Targets/NVPTX.cpp b/clang/lib/Basic/Targets/NVPTX.cpp
index a3a7bd11029ce..de99a6718f26c 100644
--- a/clang/lib/Basic/Targets/NVPTX.cpp
+++ b/clang/lib/Basic/Targets/NVPTX.cpp
@@ -66,6 +66,12 @@ NVPTXTargetInfo::NVPTXTargetInfo(const llvm::Triple &Triple,
   NoAsmVariants = true;
   GPU = OffloadArch::getUnused();
 
+  // Architectures are in the feature map only to gate builtins; the backend
+  // takes the architecture from `target-cpu`.
+#define NVPTX_GPU(NAME, KIND, VIRTUAL, SM_ID, MIN_VER, MAX_VER, SUFFIX)        \
+  ReadOnlyFeatures.insert(NAME);
+#include "llvm/TargetParser/NVPTXTargetParser.def"
+
   // PTX supports f16 as a fundamental type.
   HasFastHalfType = true;
   HasFloat16 = true;

diff  --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index eb9c8f990d923..dfacc438fe433 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3456,9 +3456,11 @@ bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
     llvm::erase_if(Features, [&](const std::string& F) {
        return getTarget().isReadOnlyFeature(F.substr(1));
     });
-    llvm::sort(Features);
-    Attrs.addAttribute("target-features", llvm::join(Features, ","));
-    AddedAttr = true;
+    if (!Features.empty()) {
+      llvm::sort(Features);
+      Attrs.addAttribute("target-features", llvm::join(Features, ","));
+      AddedAttr = true;
+    }
   }
   // Add metadata for AArch64 Function Multi Versioning.
   if (getTarget().getTriple().isAArch64()) {

diff  --git a/clang/test/CodeGen/nvptx_attributes.c b/clang/test/CodeGen/nvptx_attributes.c
index c49a68b89bc64..fbba84ff05d5a 100644
--- a/clang/test/CodeGen/nvptx_attributes.c
+++ b/clang/test/CodeGen/nvptx_attributes.c
@@ -16,7 +16,7 @@ __attribute__((nvptx_kernel)) void foo(int *ret) {
 }
 
 //.
-// CHECK: attributes #[[ATTR0]] = { convergent noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="sm_61" "target-features"="+sm_61" }
+// CHECK: attributes #[[ATTR0]] = { convergent noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="sm_61" }
 //.
 // CHECK: [[META0:![0-9]+]] = !{!"{{.*}}clang version {{.*}}"}
 //.