On 10/20/13 21:23, David Nadlinger wrote:
The documentation [1] for core.bitop.bt just says "Tests the bit."
With the function returning an int, the question is whether the return
value is guaranteed to be 0 or 1, as ensured by the current
implementation, or whether it can be any non-zero integer if the bit is
set (as documented for the related bts function).
The std.bitmanip.BitArray formatting functions in 2.064 assume the
former, and are thus currently broken with LDC. LDC will probably end up
switching to simply using the D implementation anyway as LLVM recognizes
the pattern just fine, but I'd like to know what to fix first.
David
[1] http://dlang.org/phobos/core_bitop.html
bt, bts, btr, btc all have the same return value. They only differ in
what happens with the tested bit. The fact that they return "int"
amplifies the zero / non-zero pattern.
I think BitArray should get fixed to support that definition. But you
might want to keep "bt" on LDC the same as on DMD, just to prevent
similar bugs in user's code.
L.
