Add codegen test for removing trailing zeroes from NonZero
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Aug 21, 2025
| pub fn remove_trailing_zeros(x: NonZero<u8>) -> NonZero<u8> { | ||
| // CHECK-NOT: unwrap_failed | ||
| // CHECK-NOT: br | ||
| // CHECK ret i8 |
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Maybe check the exact instruction sequence?
%0 = tail call range(i8 0, 9) i8 @llvm.cttz.i8(i8 %x, i1 true)
%n = lshr exact i8 %x, %0
ret i8 %n
It seems unlikely to change from cttz + lshr + ret, and that seems less brittle than checking for absence of particular words (br/unwrap).
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Closes #138497