[Lang] [ir] [cuda] Add clz instruction

[JettChenT]

Issue: #8212

Brief Summary

🤖 Generated by Copilot at 5d312ab

This pull request implements a new clz function in Taichi, which counts the number of leading zeros for a 32-bit integer. The function is available as a Python function decorator, a unary operation in the Taichi expression system, and a backend-specific intrinsic in the code generation. The pull request modifies the relevant files in the python, taichi, and codegen directories.

Walkthrough

🤖 Generated by Copilot at 5d312ab

• Add a new function clz to count the number of leading zeros for a 32-bit integer (link, link, link, link, link)
• Define the function clz in the ops module in python/taichi/lang/ops.py using a unary operation wrapper (link)
• Add a wrapper function clz in the mathimpl module in python/taichi/math/mathimpl.py to allow using clz as a Taichi function decorator (link)
• Add a new macro for the clz unary operation in taichi/inc/unary_op.inc.h and taichi/ir/expression_ops.h to expand to the corresponding enum value and expression class (link, link)
• Add a new macro for the clz unary operation in taichi/python/export_lang.cpp to bind the operation to the Python interface (link)
• Implement the clz unary operation for different backends (link, link, link)
  • Add a new case for the clz unary operation in the CUDA backend code generation in taichi/codegen/cuda/codegen_cuda.cpp, which calls the CUDA intrinsic function __clz and checks the input type (link)
  • Add a new case for the clz unary operation in the LLVM backend code generation in taichi/codegen/llvm/codegen_llvm.cpp, which calls the LLVM intrinsic function ctlz and assigns the result to the statement value (link)
  • Add a new case for the clz unary operation in the SPIRV backend code generation in taichi/codegen/spirv/spirv_codegen.cpp, which calls the GLSL 450 extended instruction FindMSB and subtracts the result from 32 (link)
• Add a new method for the clz unary operation in the IR builder class, which is a helper class for constructing IR statements (link, link)
  • Add a declaration for the clz unary operation method in the IR builder class header file in taichi/ir/ir_builder.h (link)
  • Add a definition for the clz unary operation method in the IR builder class source file in taichi/ir/ir_builder.cpp, which creates and inserts a new unary operation statement with the clz type and the input value (link)

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[JettChenT]

Hi! I have added the respective operators and tests into taichi, though I am not quite sure regarding whether the failed tests are a result of my addition of the clz operator (one of them seems to be a git cloning issue). Any help would be much appreciated!

[lin-hitonami]

/rebase

[lin-hitonami]

LGTM

[lin-hitonami]

Thanks! Sorry for the late review.