[llvm] [Xtensa] Implement Code Density Option. (PR #119639)

[Andrei Safronov via llvm-commits]

================
@@ -0,0 +1,64 @@
+# RUN: llvm-mc -triple=xtensa -mattr=+density -disassemble < %s | FileCheck -check-prefixes=CHECK-DENSITY %s
+# RUN: llvm-mc -triple=xtensa -disassemble %s &> %t
+# RUN: FileCheck -check-prefixes=CHECK-CORE < %t %s
+
+#------------------------------------------------------------------------------
+# Verify that binary code is correctly disassembled with
+# code density option enabled. Also verify that dissasembling without
+# density option generates warnings.
+#------------------------------------------------------------------------------
+
+0x4a 0x23
+# CHECK-DENSITY: add.n  a2, a3, a4
+# CHECK-CORE: [[#@LINE-2]]:1: warning: invalid instruction encoding
----------------
andreisfr wrote:

@MaskRay, thank you very much for comment, I'm sorry, I tried to reproduce test fail using "check-llvm" but without success, may I ask you for advice about how to reproduce the problem?

https://github.com/llvm/llvm-project/pull/119639