Reg-stack and cmove bug

[Zack Weinberg]

On Fri, Feb 16, 2001 at 07:46:24PM +0100, Jan Hubicka wrote:
> 
> Zack: can you verify that the testcase is really happy now? My patch
> changes the code in way I want, but I don't have f77 runtime to actually
> run it.

It works.  I have constructed a test case suitable for inclusion into
the test suite, and run it with and without the patch:

$ ./g77 -Bstage2/ -O2 -march=pentiumpro -ffast-math test.f \
	 -L ../i686-pc-linux-gnu/libf2c/
$ ./a.out ; echo $?
 5  9.  10.  0.100000001  0.
Fortran abort routine called
Aborted
134
$ ./g77 -B./ -O2 -march=pentiumpro -ffast-math test.f \
	 -L ../i686-pc-linux-gnu/libf2c/
$ ./a.out ; echo $?
0
$

I'm going to create a g77.dg directory for such tests and check it in
there.  The patch should be applied to the 3.0 branch as well as the
mainline; this is a regression from 2.95.

zw

C Test for bug in reg-stack handling conditional moves.
C Reported by Tim Prince <tprince@computer.org>
C
C { dg-do run { target "i[6789]86-*-*" } }
C { dg-options "-O2 -ffast-math -march=pentiumpro" }

      double precision function foo(x, y)
         implicit none
         double precision x, y
         double precision a, b, c, d
         if (x /= y) then
             if (x * y >= 0) then
                 a = abs(x)
                 b = abs(y)
                 c = max(a, b)
                 d = min(a, b)
                 foo = 1 - d/c
             else       
                 foo = 1
             end if  
         else
             foo = 0
         end if
      end

      program test
      implicit none

      integer ntests
      parameter (ntests=7)
      double precision tolerance
      parameter (tolerance=1.0D-6)

C Each column is a pair of values to feed to foo,
C and its expected return value.
      double precision a(ntests) /1, -23, -1,   1,   9,  10,  -9/
      double precision b(ntests) /1, -23, 12, -12,  10,   9, -10/
      double precision x(ntests) /0,   0,  1,   1, 0.1, 0.1, 0.1/

      double precision foo
      double precision result
      integer i

      do i = 1, ntests
         result = foo(a(i), b(i))
         if (abs(result - x(i)) > tolerance) then
           print *, i, a(i), b(i), x(i), result
           call abort
         end if
      end do
      end