[llvm-branch-commits] [clang] [flang] [llvm] [AMDGPU] More radical feature initialization refactoring (PR #155222)

[Yaxun Liu via llvm-branch-commits]

================
@@ -364,8 +364,320 @@ StringRef AMDGPU::getCanonicalArchName(const Triple &T, StringRef Arch) {
   return T.isAMDGCN() ? getArchNameAMDGCN(ProcKind) : getArchNameR600(ProcKind);
 }
 
-void AMDGPU::fillAMDGPUFeatureMap(StringRef GPU, const Triple &T,
-                                  StringMap<bool> &Features) {
+static std::pair<FeatureError, StringRef>
+insertWaveSizeFeature(StringRef GPU, const Triple &T,
+                      const StringMap<bool> &DefaultFeatures,
+                      StringMap<bool> &Features) {
+  const bool IsNullGPU = GPU.empty();
+  const bool TargetHasWave32 = DefaultFeatures.count("wavefrontsize32");
+  const bool TargetHasWave64 = DefaultFeatures.count("wavefrontsize64");
+  const bool HaveWave32 = Features.count("wavefrontsize32");
+  const bool HaveWave64 = Features.count("wavefrontsize64");
+  if (HaveWave32 && HaveWave64)
+    return {AMDGPU::INVALID_FEATURE_COMBINATION,
+            "'wavefrontsize32' and 'wavefrontsize64' are mutually exclusive"};
+
+  if (HaveWave32 && !IsNullGPU && TargetHasWave64)
+    return {AMDGPU::UNSUPPORTED_TARGET_FEATURE, "wavefrontsize32"};
+
+  if (HaveWave64 && !IsNullGPU && TargetHasWave32)
+    return {AMDGPU::UNSUPPORTED_TARGET_FEATURE, "wavefrontsize64"};
+
+  // Don't assume any wavesize with an unknown subtarget.
+  // Default to wave32 if target supports both.
+  if (!IsNullGPU && !HaveWave32 && !HaveWave64 && !TargetHasWave32 &&
+      !TargetHasWave64)
+    Features.insert(std::make_pair("wavefrontsize32", true));
+
+  for (const auto &Entry : DefaultFeatures) {
+    if (!Features.count(Entry.getKey()))
+      Features[Entry.getKey()] = Entry.getValue();
+  }
+
+  return {NO_ERROR, StringRef()};
+}
+
----------------
yxsamliu wrote:

can we add a comment that \p Features contains overriding target features and this function returns default target features with entries overridden by \p Features.

https://github.com/llvm/llvm-project/pull/155222