[llvm] [Mips] Fix missing sign extension in expansion of sub-word atomic max (PR #77072)

[via llvm-commits]

yingopq wrote:

> Hi @yingopq, thank you for the reply and for the tip. I double-checked, and I get the test failure also with [0e501db](https://github.com/llvm/llvm-project/commit/0e501dbd932ef1c6f4e747c83bf33beef0a09ecf). I also tested some extra commits just to be sure. Here are my results:
> 
> Commit	Commit info	Commit Title	Test result
> [dc39028](https://github.com/llvm/llvm-project/commit/dc39028906ba4196c3ba544c43ef6b428cf47c51)	branch main	[mlir] Fix -Wsign-compare in ValueBoundsOpInterface.cpp (NFC)	Fail
> [b6ebea7](https://github.com/llvm/llvm-project/commit/b6ebea7972cd05a8e4dcf0d5a54f2c793999995a)	branch release/18.x	[SPARC] Implement L and H inline asm argument modifiers	Fail
> [7c7c3d4](https://github.com/llvm/llvm-project/commit/7c7c3d4a3a278f70b82b4edf5bad8915d929c97d)	tag llvmorg-18.1.2 + 13	[ODS][NFC] Cast range.size() to int32_t in accumulation	Fail
> [0e501db](https://github.com/llvm/llvm-project/commit/0e501dbd932ef1c6f4e747c83bf33beef0a09ecf)	tag llvmorg-18.1.2 + 12	[Mips] Restore wrong deletion of instruction 'and' in unsigned min/max processing.	Fail
> [fbb27d1](https://github.com/llvm/llvm-project/commit/fbb27d16fa12aa595cbd20a1fb5f1c5b80748fa4)	tag llvmorg-18.1.2 + 11	[Mips] Fix missing sign extension in expansion of sub-word atomic max	Fail
> [e74c167](https://github.com/llvm/llvm-project/commit/e74c1678231ab2a7c6defe8bb90366e664780d6f)	tag llvmorg-18.1.2 + 10	[PowerPC] provide CFI for ELF32 to unwind cr2, cr3, cr4	OK
> [1c7c16e](https://github.com/llvm/llvm-project/commit/1c7c16e58240b649254536317160109478c156d1)	tag llvmorg-18.1.2 + 9	[NFC][PowerPC] use script to regenerate the CHECK lines	OK
> Please let me know if you would like me to perform more tests.

Thanks, I would check it.

https://github.com/llvm/llvm-project/pull/77072