[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 +1146,62 @@ 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 ArmStreamingInlinability : uint8_t {
+  Ok = 0,
+  IncompatibleStreamingModes = 1,
+  MismatchedStreamingCompatibility = 1 << 1,
+  CalleeHasNewZA = 1 << 2,
+  LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue=*/CalleeHasNewZA),
+};
 
+/// Determines if there are any streaming ABI issues with inlining \p Callee
+/// into \p Caller. Returns the issues in the ArmStreamingInlinability bit enum
+/// (multiple bits can be set).
+static ArmStreamingInlinability
+GetArmStreamingInlinability(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);
 
+  ArmStreamingInlinability Inlinability = ArmStreamingInlinability::Ok;
+
   if (!CalleeIsStreamingCompatible &&
-      (CallerIsStreaming != CalleeIsStreaming || CallerIsStreamingCompatible))
+      (CallerIsStreaming != CalleeIsStreaming || CallerIsStreamingCompatible)) {
+    Inlinability |= ArmStreamingInlinability::MismatchedStreamingCompatibility;
+    if (CalleeIsStreaming)
+      Inlinability |= ArmStreamingInlinability::IncompatibleStreamingModes;
+  }
+  if (auto *NewAttr = Callee->getAttr<ArmNewAttr>())
+    if (NewAttr->isNewZA())
+      Inlinability |= ArmStreamingInlinability::CalleeHasNewZA;
+
+  return Inlinability;
+}
+
+void AArch64TargetCodeGenInfo::checkFunctionCallABIStreaming(
+    CodeGenModule &CGM, SourceLocation CallLoc, const FunctionDecl *Caller,
+    const FunctionDecl *Callee) const {
+  if (!Caller || !Callee || !Callee->hasAttr<AlwaysInlineAttr>())
+    return;
+
+  ArmStreamingInlinability Inlinability =
+      GetArmStreamingInlinability(Caller, Callee);
+
+  if (bool(Inlinability &
----------------
sdesmalen-arm wrote:

nit: `bool(...)` is unnecessary?

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