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Treat TZCNT/POPCNT/LZCNT as never negative #64909
Description
A good first issue for newcomers or those who want to contribute to JIT (found in #64899 (comment), also, I used this pattern in IndexOf):
public int M1(uint x) => BitOperations.TrailingZeroCount(x) / 2;
public int M2(uint x) => (int)((uint)BitOperations.TrailingZeroCount(x) / 2);M2 emits better codegen, see sharplab
the fix is easy, IntegralRange::ForNode function should recognize GT_INTRINSIC/GT_HWINTRINSIC nodes and return non-negative range for TZCNT/POPCNT/LZCNT. Then the division will automatically be optimized.
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