[Bug rtl-optimization/106032] [12/13 Regression] wrong code at -Os and above on x86_64-linux-gnu

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106032

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |rtl-optimization

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The tree level looks ok. THe only difference is 12/13 has:

  if (c.0_1 < 0)
    goto <bb 3>; [67.00%]
  else
    goto <bb 4>; [33.00%]

  <bb 3> [local count: 679839639]:
  e_15 = *d.1_2;

  <bb 4> [local count: 59055800]:

While 11 does:
  if (c.0_1 < 0)
    goto <bb 3>; [67.00%]
  else
    goto <bb 4>; [33.00%]

  <bb 3> [local count: 679839639]:
  d.1_2 = d;
  e_15 = *d.1_2;

  <bb 4> [local count: 59055800]:

That is the load from the global d is now unconditional but the load from *d is
still conditional.

I see ce2 is doing ifcvt on that and changing it to be an unconditional load.
IF-THEN-JOIN block found, pass 1, test 3, then 4, join 5

(insn 57 56 58 2 (parallel [
            (set (reg:SI 89)
                (ashiftrt:SI (reg:SI 90 [ c ])
                    (const_int 31 [0x1f])))
            (clobber (reg:CC 17 flags))
        ]) "/app/example.cpp":7:9 758 {ashrsi3_cvt}
     (expr_list:REG_DEAD (reg:SI 90 [ c ])
        (expr_list:REG_UNUSED (reg:CC 17 flags)
            (expr_list:REG_EQUAL (ashiftrt:SI (mem/c:SI (symbol_ref:DI ("c")
[flags 0x2]  <var_decl 0x7ff174377d80 c>) [1 c+0 S4 A32])
                    (const_int 31 [0x1f]))
                (nil)))))
(insn 58 57 16 2 (parallel [
            (set (reg:SI 91)
                (and:SI (reg:SI 89)
                    (mem:SI (reg/f:DI 83 [ d.1_2 ]) [1 *d.1_2+0 S4 A32])))
            (clobber (reg:CC 17 flags))
        ]) "/app/example.cpp":7:9 533 {*andsi_1}
     (expr_list:REG_DEAD (reg:SI 89)
        (expr_list:REG_DEAD (reg/f:DI 83 [ d.1_2 ])
            (expr_list:REG_UNUSED (reg:CC 17 flags)
                (nil)))))