[Bug target/82767] [8 regression] gcc.target/i386/pr71321.c scan-assembler-times fail

[sebastian.peryt at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82767

--- Comment #3 from Sebastian Peryt <sebastian.peryt at intel dot com> ---
As per Uros's suggestion
(https://gcc.gnu.org/ml/gcc-patches/2017-11/msg00329.html ) I checked
-mtune=generic idea and this works without additional changes either in
testcase or in cost model.

>From what I gathered the cause of this test failing is below change in core
cost model:
/gcc/config/i386/x86-tune-costs.h
@@ -2253,7 +2253,7 @@ struct processor_costs core_cost = {
    COSTS_N_INSNS (4),                  /*                               DI */
    COSTS_N_INSNS (4)},                 /*                            other */
   0,                                   /* cost of multiply per each bit set */
+  {COSTS_N_INSNS (8),                  /* cost of a divide/mod for QI */
-  {COSTS_N_INSNS (18),                 /* cost of a divide/mod for QI */
    COSTS_N_INSNS (8),                  /*                          HI */
    /* 8-11 */
    COSTS_N_INSNS (11),                 /*                          SI */

Because most of Intel's CPUs are using core_cost model (including haswell) this
testcase is failing without additional tuning to generic cost model, which is
still using old cost values.