Handle mixed-width args to mul-shift-right #6526
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and codegen it to pmulhuw on x86
steven-johnson
approved these changes
Jan 3, 2022
| @@ -493,6 +494,25 @@ class FindIntrinsics : public IRMutator { | |||
| rounding_mul_shift_right(x, y, cast(unsigned_type, c0)), | |||
| is_x_same_int_or_uint && c0 >= bits) || | |||
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| // We can also match on smaller shifts if one of the args is | |||
| // narrow. We don't do this for signed (yet), because the | |||
| // saturation issue is tricky. | |||
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Do we think we will ever do so, tricky or not? (If so, tracking issue, please)
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Not sure. It depends on if it comes up in practice. It's part of the unbounded frontier of ways we could make instruction selection more clever. I don't want to add a tracking issue for each possible new way to use an instruction.
dsharletg
approved these changes
Jan 3, 2022
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and codegen it to pmulhuw on x86