[llvm] [Xtensa] Implement Windowed Register Option. (PR #121118)

[Dániel Buga via llvm-commits]

================
@@ -0,0 +1,15 @@
+# RUN: not llvm-mc -triple xtensa --mattr=+windowed %s 2>&1 | FileCheck %s
+
+# Out of range immediates
+
+# entry_imm12
+entry a3, -1
----------------
bugadani wrote:

Please test a positive parameter that is not divisible by 8 - may be 4 to catch the issue in my other comment.

https://github.com/llvm/llvm-project/pull/121118