[Bug middle-end/70424] [4.9/5/6 Regression] Pointer derived from integer gets reduced alignment

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70424

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Err

Index: gcc/ipa-prop.c
===================================================================
*** gcc/ipa-prop.c      (revision 234453)
--- gcc/ipa-prop.c      (working copy)
*************** ipa_compute_jump_functions_for_edge (str
*** 1639,1649 ****
          unsigned HOST_WIDE_INT hwi_bitpos;
          unsigned align;

!         if (get_pointer_alignment_1 (arg, &align, &hwi_bitpos)
              && align % BITS_PER_UNIT == 0
              && hwi_bitpos % BITS_PER_UNIT == 0)
            {
-             gcc_checking_assert (align != 0);
              jfunc->alignment.known = true;
              jfunc->alignment.align = align / BITS_PER_UNIT;
              jfunc->alignment.misalign = hwi_bitpos / BITS_PER_UNIT;
--- 1639,1649 ----
          unsigned HOST_WIDE_INT hwi_bitpos;
          unsigned align;

!         get_pointer_alignment_1 (arg, &align, &hwi_bitpos);
!         if (align > BITS_PER_UNIT
              && align % BITS_PER_UNIT == 0
              && hwi_bitpos % BITS_PER_UNIT == 0)
            {
              jfunc->alignment.known = true;
              jfunc->alignment.align = align / BITS_PER_UNIT;
              jfunc->alignment.misalign = hwi_bitpos / BITS_PER_UNIT;