GPU data tiling: Refine tile dimensions, more preparation for thread distribution.

[bjacob]

• The unrolling factors in DataTiledMMAAttr get split between plain unrolling and unroll-to-subgroups.
• The dimensions in TileSwizzle get an enum telling if they are cross-thread / cross-instruction.
• getSwizzle gets moved to GPUTileSwizzleUtils as it is going to be used in codegen outside of MaterializeEncoding.

[bjacob]

I had a change of heart and decided that an enum was better after all. The thing that changed since I had earlier favored separate booleans, is that regarding the unrolling dimensions, we are now splitting them into separate unroll-to-subgroups vs plain unroll dimensions. The former are cross-thread, the latter are cross-intrinsic. Thus, we never anymore have a dimensions that's simultaneously cross-thread and cross-intrinsic, so these things aren't orthogonal after all. The last commit added to this PR implements that change. @Max191 @qedawkins .

[hanhanW]

Just few nits. I'll need to learn more about the intention of Kind enum class. Let's catch up on Wed.

[Max191]

Looks good! Just leaving a reminder to update the comments as we discussed offline.

[ScottTodd]

This broke the gcc build: https://github.com/iree-org/iree/actions/runs/11030265747/job/30634464951#step:4:6937

[6307/8097] Building CXX object compiler/src/iree/compiler/Codegen/Common/CMakeFiles/iree_compiler_Codegen_Common_Common.objects.dir/TileSwizzle.cpp.o
FAILED: compiler/src/iree/compiler/Codegen/Common/CMakeFiles/iree_compiler_Codegen_Common_Common.objects.dir/TileSwizzle.cpp.o 
/usr/local/bin/ccache /usr/bin/g++-9  -I/__w/iree/iree -I/__w/iree/iree/build-gcc -I/__w/iree/iree/third_party/llvm-project/llvm/include -I/__w/iree/iree/build-gcc/llvm-project/include -I/__w/iree/iree/third_party/llvm-project/mlir/include -I/__w/iree/iree/build-gcc/llvm-project/tools/mlir/include -I/__w/iree/iree/third_party/llvm-project/lld/include -I/__w/iree/iree/build-gcc/llvm-project/tools/lld/include -I/__w/iree/iree/compiler/src -I/__w/iree/iree/build-gcc/compiler/src -I/__w/iree/iree/runtime/src -I/__w/iree/iree/build-gcc/runtime/src -I/__w/iree/iree/build-gcc/runtime/src/iree/base/internal/flatcc -I/__w/iree/iree/llvm-external-projects/iree-dialects/include -I/__w/iree/iree/build-gcc/llvm-external-projects/mlir-iree-dialects/include -isystem /__w/iree/iree/third_party/flatcc/include -O3  -fPIC -fvisibility=hidden -fno-rtti -fno-exceptions -Wall -Werror -Wno-error=deprecated-declarations -Wno-address -Wno-address-of-packed-member -Wno-comment -Wno-format-zero-length -Wno-uninitialized -Wno-overloaded-virtual -Wno-invalid-offsetof -Wno-sign-compare -Wno-unused-function -Wno-unknown-pragmas -Wno-unused-but-set-variable -Wno-misleading-indentation -fmacro-prefix-map=/__w/iree/iree=iree -I/__w/iree/iree/third_party/flatcc/include/ -I/__w/iree/iree/third_party/flatcc/include/flatcc/reflection/ -std=gnu++17 -MD -MT compiler/src/iree/compiler/Codegen/Common/CMakeFiles/iree_compiler_Codegen_Common_Common.objects.dir/TileSwizzle.cpp.o -MF compiler/src/iree/compiler/Codegen/Common/CMakeFiles/iree_compiler_Codegen_Common_Common.objects.dir/TileSwizzle.cpp.o.d -o compiler/src/iree/compiler/Codegen/Common/CMakeFiles/iree_compiler_Codegen_Common_Common.objects.dir/TileSwizzle.cpp.o -c /__w/iree/iree/compiler/src/iree/compiler/Codegen/Common/TileSwizzle.cpp
/__w/iree/iree/compiler/src/iree/compiler/Codegen/Common/TileSwizzle.cpp: In function 'llvm::raw_ostream& mlir::iree_compiler::operator<<(llvm::raw_ostream&, mlir::iree_compiler::TileSwizzle::Dim::Kind)':
/__w/iree/iree/compiler/src/iree/compiler/Codegen/Common/TileSwizzle.cpp:22:1: error: control reaches end of non-void function [-Werror=return-type]
   22 | }
      | ^
cc1plus: all warnings being treated as errors

Could assert on the default / fallthrough case, or implement some logic in case an unhandled enum value gets passed in.

[bjacob]

Thanks for flagging! I have added a fix to #18547 which I'm about to merge.