[llvm] [Mips] In LowerShift*Parts, xor with bits-1 instead of -1. (PR #71149)

[Simon Pilgrim via llvm-commits]

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@@ -2593,12 +2593,13 @@ SDValue MipsTargetLowering::lowerShiftLeftParts(SDValue Op,
   SDValue Shamt = Op.getOperand(2);
   // if shamt < (VT.bits):
   //  lo = (shl lo, shamt)
-  //  hi = (or (shl hi, shamt) (srl (srl lo, 1), ~shamt))
+  //  hi = (or (shl hi, shamt) (srl (srl lo, 1), (VT.bits-1) ^ shamt))
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RKSimon wrote:

consistent style: (xor (VT.bits-1), shamt)

https://github.com/llvm/llvm-project/pull/71149