[Clang][AArch64] Add pessimistic vscale_range for sve/sme (#137624)

The "target-features" function attribute is not currently considered
when adding vscale_range to a function. When +sve/+sme are pushed onto
functions with "#pragma attribute push(+sve/+sme)", the function
potentially misses out on optimizations that rely on vscale_range being
present.

1 files changed, 8 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index d773cdd..ac40aab 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1115,9 +1115,15 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
     Fn->removeFnAttr("zero-call-used-regs");
 
   // Add vscale_range attribute if appropriate.
+  llvm::StringMap<bool> FeatureMap;
+  bool IsArmStreaming = false;
+  if (FD) {
+    getContext().getFunctionFeatureMap(FeatureMap, FD);
+    IsArmStreaming = IsArmStreamingFunction(FD, true);
+  }
   std::optional<std::pair<unsigned, unsigned>> VScaleRange =
-      getContext().getTargetInfo().getVScaleRange(
-          getLangOpts(), FD ? IsArmStreamingFunction(FD, true) : false);
+      getContext().getTargetInfo().getVScaleRange(getLangOpts(), IsArmStreaming,
+                                                  &FeatureMap);
   if (VScaleRange) {
     CurFn->addFnAttr(llvm::Attribute::getWithVScaleRangeArgs(
         getLLVMContext(), VScaleRange->first, VScaleRange->second));