David Green
3273cdaa5e
Given an instruction with a non-concrete type (G_CONCAT_VECTOR), with a child pattern instruction with a concrete type (G_FPTRUNC), the concrete type check for the child would incorrectly be removed. This patch makes sure they remain. This makes the match table a little larger, but many should be able to be optimized away (providing that the two operands with the same type can be matched up). Fixes #221458 (cherry picked from commit 09be00c800cf9ae03a2c8fbdc215c259ac39f30f)
LLVM TableGen
The purpose of TableGen is to generate complex output files based on information from source files that are significantly easier to code than the output files would be, and also easier to maintain and modify over time.
The information is coded in a declarative style involving classes and records, which are then processed by TableGen.
class Hello <string _msg> {
string msg = !strconcat("Hello ", _msg);
}
def HelloWorld: Hello<"world!"> {}
------------- Classes -----------------
class Hello<string Hello:_msg = ?> {
string msg = !strconcat("Hello ", Hello:_msg);
}
------------- Defs -----------------
def HelloWorld { // Hello
string msg = "Hello world!";
}
Try this example on Compiler Explorer.
The internalized records are passed on to various backends, which extract information from a subset of the records and generate one or more output files.
These output files are typically .inc files for C++, but may be any type of file that the backend developer needs.
Resources for learning the language:
- TableGen Overview
- Tutorial
- Programmer's reference guide
- Tools for Learning LLVM TableGen
- Lessons in TableGen (video), slides
- Improving Your TableGen Descriptions (video), slides
Writing TableGen backends:
- TableGen Backend Developer's Guide
- How to write a TableGen backend (video), slides, also available as a notebook.
TableGen in MLIR:
Useful tools: