This PR continues https://github.com/llvm/llvm-project/pull/101732
changes in virtual register processing aimed to improve correctness of
emitted MIR between passes from the perspective of MachineVerifier.
Namely, the following changes are introduced:
* register classes (lib/Target/SPIRV/SPIRVRegisterInfo.td) and
instruction patterns (lib/Target/SPIRV/SPIRVInstrInfo.td) are corrected
and simplified (by removing unnecessary sophisticated options) -- e.g.,
this PR gets rid of duplicating 32/64 bits patterns, removes ANYID
register class and simplifies definition of the rest of register
classes,
* hardcoded LLT scalar types in passes before instruction selection are
corrected -- the goal is to have correct bit width before instruction
selection, and use 64 bits registers for pattern matching in the
instruction selection pass; 32-bit registers remain where they are
described in such terms by SPIR-V specification (like, for example,
creation of virtual registers for scope/mem semantics operands),
* rework virtual register type/class assignment for calls/builtins
lowering,
* a series of minor changes to fix validity of emitted code between
passes:
- ensure that that bitcast changes the type,
- fix the pattern for instruction selection for OpExtInst,
- simplify inline asm operands usage,
- account for arbitrary integer sizes / update legalizer rules;
* add '-verify-machineinstrs' to existed test cases.
See also https://github.com/llvm/llvm-project/issues/88129 that this PR
may resolve.
This PR fixes a great number of issues reported by MachineVerifier and,
as a result, reduces a number of failed test cases for the mode with
expensive checks set on from ~200 to ~57.
This PR introduces a step after instruction selection where instructions
can be traversed from the perspective of their validity from the
specification point of view. The PR adds also a way to correct
load/store when there is a type mismatch contradicting the specification
-- an additional bitcast is inserted to keep types consistent.
Correspondent test cases are added and existing test cases are
corrected.
This PR helps to successfully validate with the `spirv-val` tool
(https://github.com/KhronosGroup/SPIRV-Tools) some output that
previously led to validation errors and crashes of back translation from
SPIRV to LLVM IR from the side of SPIRV Translator project
(https://github.com/KhronosGroup/SPIRV-LLVM-Translator).
The added step of bringing instructions to required by the specification
type correspondence can be (should be and will be) extended beyond
load/store instructions to ensure validity rules of other SPIRV
instructions related to type inference.
