The following testcase started to ICE when .POPCOUNT matching has been added
to match.pd; we had __builtin_popcount*, but nothing would use the
popcounthi2 expander before.
The problem is that the popcounthi2_z196 expander doesn't emit valid RTL:
error: unrecognizable insn:
(insn 138 137 139 27 (set (reg:SI 190)
(ashift:SI (reg:HI 95 [ _105 ])
(const_int 8 [0x8]))) -1
(nil))
during RTL pass: vregs
The following patch is an attempt to fix that, furthermore I've tried to
slightly simplify it as well, it makes no sense to me to perform
(x + (x << 8)) >> 8 when we need to either zero extend or mask the result
at the end in order to avoid bits from above HImode to affect it, when we
can do
(x + (x >> 8)) & 0xff (or zero extension).
2020-02-03 Jakub Jelinek <jakub@redhat.com>
PR target/93533
* config/s390/s390.md (popcounthi2_z196): Fix up expander to emit
valid RTL to sum up the lowest and second lowest bytes of the popcnt
result.
* gcc.c-torture/compile/pr93533.c: New test.
* gcc.target/s390/pr93533.c: New test.
