[Coroutines] Take byval param alignment into account when spilling to frame (#159765)

Fixes #159571

Author: zmodem

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -907,13 +907,17 @@ static StructType *buildFrameType(Function &F, coro::Shape &Shape,
   // Create an entry for every spilled value.
   for (auto &S : FrameData.Spills) {
     Type *FieldType = S.first->getType();
+    MaybeAlign MA;
     // For byval arguments, we need to store the pointed value in the frame,
     // instead of the pointer itself.
-    if (const Argument *A = dyn_cast<Argument>(S.first))
-      if (A->hasByValAttr())
+    if (const Argument *A = dyn_cast<Argument>(S.first)) {
+      if (A->hasByValAttr()) {
         FieldType = A->getParamByValType();
-    FieldIDType Id = B.addField(FieldType, std::nullopt, false /*header*/,
-                                true /*IsSpillOfValue*/);
+        MA = A->getParamAlign();
+      }
+    }
+    FieldIDType Id =
+        B.addField(FieldType, MA, false /*header*/, true /*IsSpillOfValue*/);
     FrameData.setFieldIndex(S.first, Id);
   }
 

llvm/test/Transforms/Coroutines/coro-byval-param.ll

@@ -56,8 +56,9 @@ coro.ret:                                         ; preds = %coro.free, %cleanup
   ret ptr %call2
 }
 
-; check that the frame contains the entire struct, instead of just the struct pointer
-; CHECK: %foo.Frame = type { ptr, ptr, %promise_type, %struct.A, i1 }
+; check that the frame contains the entire struct, instead of just the struct pointer,
+; and that the alignment is taken into account.
+; CHECK: %foo.Frame = type { ptr, ptr, %promise_type, i1, [6 x i8], %struct.A }
 
 ; Function Attrs: argmemonly nounwind readonly
 declare token @llvm.coro.id(i32, ptr readnone, ptr nocapture readonly, ptr) #1