Like any other instruction with 32-bit GPR destination operand in 64-bit
mode, popcntl also clears the upper 32 bits of the register (and other bits
too, it can return only 0 to 32 inclusive).
During combine, the zero or sign extensions of it show up as paradoxical
subreg of the popcount & 63, there 63 is the smallest power of two - 1 mask
that can represent all the 0 to 32 inclusive values.
2020-01-30 Jakub Jelinek <jakub@redhat.com>
PR target/91824
* config/i386/i386.md (*popcountsi2_zext): New define_insn_and_split.
(*popcountsi2_zext_falsedep): New define_insn.
* gcc.target/i386/pr91824-1.c: New test.
