[llvm] [TargetLowering] Change subtraction to do (LHS < RHS) XOR (RESULT < 0) (PR #150872)

[Jay Foad via llvm-commits]

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@@ -11447,13 +11447,25 @@ void TargetLowering::expandSADDSUBO(
   // For a subtraction, the result should be less than one of the operands
   // (LHS) if and only if the other operand (RHS) is (non-zero) positive,
   // otherwise there will be overflow.
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jayfoad wrote:

Remove the old comment.

https://github.com/llvm/llvm-project/pull/150872