GCC trunk SPEC2000 performance

[David Edelsohn]

>>>>> Graham Stott writes:

Graham> That all depends if a MEM rtx should ever appear in x_regno_reg_rtx[]

Graham> I can't tell for sure because there's no comment describing this field
Graham> in integrate.h and a quick grep is not conclusive most of the uses I
Graham> examined implied it was always a REG rtx but in a few cases there is
Graham> code such as

Graham> if (GET_CODE (regno_reg_rtx[regno]) != REG)

Graham> which tends to imply it might sometimes not be a REG rtx.

	reload1.c has the comment:

  /* If the reg got changed to a MEM at rtl-generation time,
     ignore it.  */
  if (GET_CODE (regno_reg_rtx[i]) != REG)
    return;

which strongly implies that the array can contain MEMs created at RTL
generation, so assuming that the array only contains REGs is incorrect.

David