[clang] [clang][SME] Ignore flatten/clang::always_inline statements for callees with mismatched streaming attributes (PR #116391)

[Sander de Smalen via cfe-commits]

================
@@ -1143,30 +1146,63 @@ void AArch64TargetCodeGenInfo::checkFunctionABI(
   }
 }
 
-void AArch64TargetCodeGenInfo::checkFunctionCallABIStreaming(
-    CodeGenModule &CGM, SourceLocation CallLoc, const FunctionDecl *Caller,
-    const FunctionDecl *Callee) const {
-  if (!Caller || !Callee || !Callee->hasAttr<AlwaysInlineAttr>())
-    return;
+enum class ArmSMEInlinability : uint8_t {
+  Ok = 0,
+  MismatchedStreamingCompatibility = 1 << 0,
+  IncompatibleStreamingModes = 1 << 1,
+  CalleeRequiresNewZA = 1 << 2,
+  LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue=*/CalleeRequiresNewZA),
+};
 
+/// Determines if there are any Arm SME ABI issues with inlining \p Callee into
+/// \p Caller. Returns the issues in the ArmSMEInlinability bit enum (multiple
+/// bits can be set).
+static ArmSMEInlinability GetArmSMEInlinability(const FunctionDecl *Caller,
+                                                const FunctionDecl *Callee) {
   bool CallerIsStreaming =
       IsArmStreamingFunction(Caller, /*IncludeLocallyStreaming=*/true);
   bool CalleeIsStreaming =
       IsArmStreamingFunction(Callee, /*IncludeLocallyStreaming=*/true);
   bool CallerIsStreamingCompatible = isStreamingCompatible(Caller);
   bool CalleeIsStreamingCompatible = isStreamingCompatible(Callee);
 
+  ArmSMEInlinability Inlinability = ArmSMEInlinability::Ok;
+
   if (!CalleeIsStreamingCompatible &&
-      (CallerIsStreaming != CalleeIsStreaming || CallerIsStreamingCompatible))
-    CGM.getDiags().Report(
-        CallLoc, CalleeIsStreaming
-                     ? diag::err_function_always_inline_attribute_mismatch
-                     : diag::warn_function_always_inline_attribute_mismatch)
-        << Caller->getDeclName() << Callee->getDeclName() << "streaming";
+      (CallerIsStreaming != CalleeIsStreaming || CallerIsStreamingCompatible)) {
+    Inlinability |= ArmSMEInlinability::MismatchedStreamingCompatibility;
+    if (CalleeIsStreaming)
+      Inlinability |= ArmSMEInlinability::IncompatibleStreamingModes;
+  }
----------------
sdesmalen-arm wrote:

I would suggest splitting out both cases so that only one of the two values is ever set, and then use the mask suggested in my other comment to test if either of the values is set.

https://github.com/llvm/llvm-project/pull/116391