[AArch64][GlobalISel] Add test coverage for arm64-vcvtxd_f32_f64.ll. NFC

Author: davemgreen

llvm/test/CodeGen/AArch64/arm64-vcvtxd_f32_f64.ll

@@ -1,11 +1,14 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc < %s -mtriple=arm64-eabi | FileCheck %s
+; RUN: llc < %s -mtriple=arm64-eabi -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK,CHECK-GI
+
+; CHECK-GI:       warning: Instruction selection used fallback path for fcvtxn
 
 define float @fcvtxn(double %a) {
 ; CHECK-LABEL: fcvtxn:
-; CHECK: fcvtxn s0, d0
-; CHECK-NEXT: ret
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    fcvtxn s0, d0
+; CHECK-NEXT:    ret
   %vcvtxd.i = tail call float @llvm.aarch64.sisd.fcvtxn(double %a) nounwind
   ret float %vcvtxd.i
 }
-
-declare float @llvm.aarch64.sisd.fcvtxn(double) nounwind readnone