[Fix] eliminate llvm unsupported type (Float8/4) before llvm conversion

[sjfeng1999]

Motivation

Technical Details

Test Plan

Test Result

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[Copilot]

Pull request overview

This PR updates Fly’s register-to-SSA promotion and Fly→ROCDL lowering to proactively eliminate LLVM-unsupported small-float element types (e.g., fp8/fp4) by projecting them to same-bitwidth integer types before LLVM dialect conversion.

Changes:

• Introduces projectToLLVMCompatibleElemTy and extends RegMem2SSAType(..., llvmCompatibleType=true) to project small floats to same-width integers.
• Updates regmem promotion + atom-call SSA conversion paths to use LLVM-compatible SSA element types (with bitcasts as needed).
• Extends Fly→ROCDL type conversion and adds/updates MLIR tests covering fp8 SSA MMA lowering.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/mlir/Transforms/promote_regmem_to_ssa.mlir	Updates FileCheck expectations to reflect fp8→i8 vector bitcasts during regmem-to-SSA promotion.
tests/mlir/Conversion/mma_atom.mlir	Adds a conversion test ensuring fp8 SSA MMA uses vector<8xi8> and lowers via llvm.bitcast to i64 for MFMA.
lib/Dialect/FlyROCDL/GFX1250/MmaAtom.cpp	Bitcasts SSA inputs to expected ROCDL operand/accumulator types before WMMA emission.
lib/Dialect/FlyROCDL/CDNA4/CopyAtom.cpp	Requests LLVM-compatible SSA types for register memrefs in copy atom lowering.
lib/Dialect/FlyROCDL/CDNA3/MmaAtom.cpp	Bitcasts SSA inputs to expected MFMA operand/accumulator types; removes unused includes.
lib/Dialect/FlyROCDL/CDNA3/CopyAtom.cpp	Requests LLVM-compatible SSA types for register memrefs; fixes switch completeness in getFieldIndex.
lib/Dialect/Fly/Utils/PointerUtils.cpp	Implements projectToLLVMCompatibleElemTy and adds llvmCompatibleType control to RegMem2SSAType.
lib/Dialect/Fly/Transforms/PromoteRegMemToVectorSSA.cpp	Promotes regmem SSA vectors using LLVM-compatible element types and inserts element-type bitcasts.
lib/Dialect/Fly/Transforms/ConvertAtomCallToSSAForm.cpp	Loads/stores promoted regmem using LLVM-compatible SSA types for atom-call SSA conversion.
lib/Dialect/Fly/IR/FlyUniversalOps.cpp	Uses LLVM-compatible SSA types for universal atomic copy lowering.
lib/Conversion/FlyToROCDL/FlyToROCDL.cpp	Projects small-float element types for alloca/GEP and adds type-converter rules for small-float→int (including vectors).
include/flydsl/Dialect/Fly/Utils/PointerUtils.h	Declares new projection helper and extends RegMem2SSAType API.

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