[clang][bytecode] Handle non-primitive vector element types (llvm#124926)

By rejecting them. We would crash before.

Author: tbaederr

clang/lib/AST/ByteCode/Program.cpp

@@ -453,15 +453,21 @@ Descriptor *Program::createDescriptor(const DeclTy &D, const Type *Ty,
 
   // Complex types - represented as arrays of elements.
   if (const auto *CT = Ty->getAs<ComplexType>()) {
-    PrimType ElemTy = *Ctx.classify(CT->getElementType());
-    return allocateDescriptor(D, ElemTy, MDSize, 2, IsConst, IsTemporary,
+    std::optional<PrimType> ElemTy = Ctx.classify(CT->getElementType());
+    if (!ElemTy)
+      return nullptr;
+
+    return allocateDescriptor(D, *ElemTy, MDSize, 2, IsConst, IsTemporary,
                               IsMutable);
   }
 
   // Same with vector types.
   if (const auto *VT = Ty->getAs<VectorType>()) {
-    PrimType ElemTy = *Ctx.classify(VT->getElementType());
-    return allocateDescriptor(D, ElemTy, MDSize, VT->getNumElements(), IsConst,
+    std::optional<PrimType> ElemTy = Ctx.classify(VT->getElementType());
+    if (!ElemTy)
+      return nullptr;
+
+    return allocateDescriptor(D, *ElemTy, MDSize, VT->getNumElements(), IsConst,
                               IsTemporary, IsMutable);
   }
 

clang/test/AST/ByteCode/neon.c

@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +neon -disable-O0-optnone -emit-llvm -o - %s -fexperimental-new-constant-interpreter
+
+// REQUIRES: aarch64-registered-target
+
+/// This just tests that we're not crashing with a non-primitive vector element type.
+
+typedef __mfp8 mfloat8_t;
+typedef __bf16 bfloat16_t;
+
+typedef __attribute__((neon_vector_type(8))) mfloat8_t mfloat8x8_t;
+typedef __attribute__((neon_vector_type(8))) bfloat16_t bfloat16x8_t;
+
+typedef __UINT64_TYPE__ fpm_t;
+#define __ai static __inline__ __attribute__((__always_inline__, __nodebug__))
+__ai __attribute__((target("fp8,neon"))) bfloat16x8_t vcvt1_bf16_mf8_fpm(mfloat8x8_t __p0, fpm_t __p1) {
+  bfloat16x8_t __ret;
+  __ret = (bfloat16x8_t) __builtin_neon_vcvt1_bf16_mf8_fpm(__p0, __p1);
+  return __ret;
+}