MIPS patch: fix incorrectly inverted branch

[Richard Sandiford <r dot sandiford at redhat dot com>]

Testcase: attached
Target: mips64-elf -mips3

This patch fixes a problem with gen_int_relational's handling of X != 0
comparisons, where X is not a register.  When called by branch-generating
functions, gen_int_relational is passed a pointer to a boolean flag that
gets set if the branch should be reversed.  In the case of X != 0,
gen_int_relational first assumes it will generate an inverted condition, and
that a reversed branch is therefore needed.  It later realises it can create
a non-inverted condition after all, but doesn't change its decision to
reverse the branch.  In the test case below, the "then" and "else" clauses
are effectively reversed.

Patch was tested on a i686-linux-gnu-x-mips64-elf toolchain with -mips3.
Fixes the test case below & introduces no regressions.


2001-06-22  Richard Sandiford  <rsandifo@redhat.com>

	* config/mips/mips.c (gen_int_relational): Tell the caller not to
	reverse a branch if a NE comparison is implemented with GTU.

Index: mips.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/mips/mips.c,v
retrieving revision 1.117
diff -c -p -d -r1.117 mips.c
*** mips.c	2001/05/31 19:39:30	1.117
--- mips.c	2001/06/22 13:41:15
*************** gen_int_relational (test_code, result, c
*** 2965,2971 ****
        if (! TARGET_MIPS16)
  	{
  	  convert_move (result, gen_rtx (GTU, mode, reg, const0_rtx), 0);
! 	  invert = 0;
  	}
        else
  	{
--- 2965,2974 ----
        if (! TARGET_MIPS16)
  	{
  	  convert_move (result, gen_rtx (GTU, mode, reg, const0_rtx), 0);
! 	  if (p_invert != NULL)
! 	    *p_invert = 0;
! 	  else
! 	    invert = 0;
  	}
        else
  	{

Test case:

void foo (int *a) {}

int main ()
{
  int a;
  if (&a == 0)
    abort ();
  else
    {
      foo (&a);
      exit (0);
    }
}