On 2/1/20 9:41 PM, Jakub Jelinek wrote:
> Hi!
>
> 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).
>
> Bootstrapped/regtested on s390x-linux, ok for trunk?
Ok. Thanks for the fix!
Andreas
>
> 2020-02-01 Jakub jelinek <ja...@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/config/s390/s390.md.jj 2020-01-12 11:54:36.412413424 +0100
> +++ gcc/config/s390/s390.md 2020-02-01 13:34:21.671431689 +0100
> @@ -11670,21 +11670,28 @@ (define_expand "popcountsi2"
> })
>
> (define_expand "popcounthi2_z196"
> - [; popcnt op0, op1
> - (parallel [(set (match_operand:HI 0 "register_operand" "")
> + [; popcnt op2, op1
> + (parallel [(set (match_dup 2)
> (unspec:HI [(match_operand:HI 1 "register_operand")]
> UNSPEC_POPCNT))
> (clobber (reg:CC CC_REGNUM))])
> - ; sllk op2, op0, 8
> - (set (match_dup 2)
> - (ashift:SI (match_dup 0) (const_int 8)))
> - ; ar op0, op2
> - (parallel [(set (match_dup 0) (plus:SI (match_dup 0) (match_dup 2)))
> + ; lr op3, op2
> + (set (match_dup 3) (subreg:SI (match_dup 2) 0))
> + ; srl op4, op3, 8
> + (set (match_dup 4) (lshiftrt:SI (match_dup 3) (const_int 8)))
> + ; ar op3, op4
> + (parallel [(set (match_dup 3) (plus:SI (match_dup 3) (match_dup 4)))
> (clobber (reg:CC CC_REGNUM))])
> - ; srl op0, op0, 8
> - (set (match_dup 0) (lshiftrt:HI (match_dup 0) (const_int 8)))]
> + ; llgc op0, op3
> + (parallel [(set (match_operand:HI 0 "register_operand" "")
> + (and:HI (subreg:HI (match_dup 3) 2) (const_int 255)))
> + (clobber (reg:CC CC_REGNUM))])]
> "TARGET_Z196"
> - "operands[2] = gen_reg_rtx (SImode);")
> +{
> + operands[2] = gen_reg_rtx (HImode);
> + operands[3] = gen_reg_rtx (SImode);
> + operands[4] = gen_reg_rtx (SImode);
> +})
>
> (define_expand "popcounthi2"
> [(set (match_dup 2)
> --- gcc/testsuite/gcc.c-torture/compile/pr93533.c.jj 2020-02-01
> 13:44:16.296681108 +0100
> +++ gcc/testsuite/gcc.c-torture/compile/pr93533.c 2020-02-01
> 13:43:52.034038073 +0100
> @@ -0,0 +1,9 @@
> +/* PR target/93533 */
> +
> +unsigned
> +foo (unsigned short a)
> +{
> + a = a - (a >> 1 & 21845);
> + a = (a & 13107) + (a >> 2 & 13107);
> + return (unsigned short) ((a + (a >> 4) & 3855) * 257) >> 8;
> +}
> --- gcc/testsuite/gcc.target/s390/pr93533.c.jj 2020-02-01
> 13:45:41.433428499 +0100
> +++ gcc/testsuite/gcc.target/s390/pr93533.c 2020-02-01 13:45:32.984552824
> +0100
> @@ -0,0 +1,5 @@
> +/* PR target/93533 */
> +/* { dg-do compile } */
> +/* { dg-options "-march=z196 -O2" } */
> +
> +#include "../../gcc.c-torture/compile/pr93533.c"
>
> Jakub
>
