[clang] [llvm] [PowerPC] Add intrinsics for rldimi/rlwimi/rlwnm (PR #82968)

[Chen Zheng via cfe-commits]

================
@@ -10722,6 +10723,20 @@ static bool getVectorCompareInfo(SDValue Intrin, int &CompareOpc,
   return true;
 }
 
+bool isContiguousMask(const APInt &Val, unsigned &MB, unsigned &ME,
----------------
chenzheng1030 wrote:

Is it possible to reuse `isRunOfOnes()`/`isRunOfOnes64()` in `llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h`?

https://github.com/llvm/llvm-project/pull/82968