re PR middle-end/56420 (Arithmetic error in computation with compile time unsigned __int128 constant)
PR middle-end/56420
* expmed.c (EXACT_POWER_OF_2_OR_ZERO_P): Do subtraction in uhwi, to
avoid signed wrapping.
(expand_mult): Handle properly multiplication by
((dword_type) -1) << (BITS_PER_WORD - 1). Improve multiplication by
((dword_type) 1) << (BITS_PER_WORD - 1). Avoid undefined behavior
in the compiler if coeff is HOST_WIDE_INT_MIN.
(expand_divmod): Don't make ext_op1 static, change it's type to
uhwi. Avoid undefined behavior in -INTVAL (op1).
* gcc.dg/torture/pr56420.c: New test.
From-SVN: r196215
