[clang] [llvm] [RISCV] Add MIPS extensions (PR #121394)

[Craig Topper via llvm-commits]

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@@ -109,6 +109,21 @@ def uimm7_lsb00 : RISCVOp,
   }];
 }
 
+// A 7-bit unsigned immediate where the least significant three bits are zero.
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topperc wrote:

This should be defned in Mips specific file if that's the only place it is used.

https://github.com/llvm/llvm-project/pull/121394