89e64bc030
The old assignment to bitwidth was before we handled VOIDmode with:
if (mode == VOIDmode)
mode = GET_MODE (x);
so when VOIDmode was specified we would always use:
if (bitwidth < GET_MODE_PRECISION (GET_MODE (x)))
{
num0 = cached_num_sign_bit_copies (x, GET_MODE (x),
known_x, known_mode, known_ret);
return MAX (1,
num0 - (int) (GET_MODE_PRECISION (GET_MODE (x)) - bitwidth));
}
For a zero bitwidth this always returns 1 (which is the most
pessimistic result).
gcc/
2016-11-15 Richard Sandiford <richard.sandiford@arm.com>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
* rtlanal.c (num_sign_bit_copies1): Calculate bitwidth after
handling VOIDmode.
Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r242440
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