[llvm] [ADT] Add implementations for mulhs and mulhu to APInt (PR #84609)

[Shourya Goel via llvm-commits]

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@@ -3067,6 +3067,22 @@ void llvm::StoreIntToMemory(const APInt &IntVal, uint8_t *Dst,
   }
 }
 
+APInt APIntOps::mulhu(const APInt &C1, const APInt &C2) {
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Sh0g0-1758 wrote:

It should be `C1.getBitWidth()`. Updated the code with it. 

https://github.com/llvm/llvm-project/pull/84609