A bug in reg-stack.c

A bug in reg-stack.c

[H.J. Lu]

Hi,

reg-stack.c has quite a few bugs. Here is a test case.

# gcc cc -S -O2 980313-1.c
cc: Internal compiler error: program cc1 got fatal signal 6

The problem is in compare_for_stack_reg (). Around line 2063, there
are

  replace_reg (src1, FIRST_STACK_REG);
   
  if (STACK_REG_P (*src2))
    replace_reg (src2, get_hard_regnum (regstack, *src2));

  if (src1_note)
    {
      CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (XEXP (src1_note, 0)));
      replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
      regstack->top--;
    }

That is quite bogus since probably REGNO (XEXP (src1_note, 0)) !=
FIRST_STACK_REG. regstack->top-- is not correct to remove the dead
register. Could someone please take a look?

Thanks.


-- 
H.J. Lu (hjl@gnu.org)
---980313-1.c-----
/* { dg-do compile { target i?86-*-* } } */
/* { dg-options "-O2 -mach=pentiumpro" } */

extern __inline  double
__expm1 (double __x)
{
  double __temp;
  __temp -= 1.0;
  return __temp;
}
extern __inline  double
__sgn1 (double __x)
{
  return __x >= 0.0 ? 1.0 : -1.0;
}
double
tanh (double __x)
{
  register double __exm1 = __expm1 (__x);
  return __exm1 / (__exm1 + 2.0) * __sgn1 (-__x);
}

Re: A bug in reg-stack.c

[Jim Wilson]

	reg-stack.c has quite a few bugs. Here is a test case.

Thanks.  I added this testcase for the reg-stack.c bug.

Jim