Add .gitignore file.

The file contents are mostly copied from upstream LLVM.

Author: tsymalla-AMD

.gitignore

@@ -0,0 +1,45 @@
+#==============================================================================#
+# File extensions to be ignored anywhere in the tree.
+# Derived from LLVM (https://github.com/llvm/llvm-project/blob/main/.gitignore).
+#==============================================================================#
+# Temp files created by most text editors.
+*~
+# Merge files created by git.
+*.orig
+# Reject files created by patch.
+*.rej
+# Byte compiled python modules.
+*.pyc
+# vim swap files
+.*.sw?
+.sw?
+#OS X specific files.
+.DS_store
+
+# Ignore the user specified CMake presets in subproject directories.
+/*/CMakeUserPresets.json
+
+# Nested build directory
+/build*
+
+#==============================================================================#
+# Explicit files to ignore (only matches one).
+#==============================================================================#
+.gitusers
+/compile_commands.json
+# Visual Studio built-in CMake configuration
+/CMakeSettings.json
+# CLion project configuration
+/.idea
+
+#==============================================================================#
+# Directories to ignore (do not add trailing '/'s, they skip symlinks).
+#==============================================================================#
+# VS2017 and VSCode config files.
+.vscode
+.vs
+# pythonenv for github Codespaces
+pythonenv*
+# clangd index. (".clangd" is a config file now, thus trailing slash)
+.clangd/
+.cache