FIX: DO Loop/Computed GOTO Errors with /Ox and /4Yb

MORE INFORMATION

The following code illustrates the DO loop problem when compiling with /Ox and /4Yb:

Sample Code #1

c FORTRAN Compile options needed: /Ox /4Yb
      ieof = 0
      DO i = 1, 4
        IF ( i .EQ. 4 )  ieof = 999
        i1 = i + 1
        WRITE (*,1000) i, i1, ieof
      ENDDO
1000  FORMAT (3i6)
      END
				

Output

Expected results:

   1     2     0
   2     3     0
   3     4     0
   4     5   999
				

Results with -Ox -4Yb:

   1     2     0
   1     2     0
   2     3     0
   3     4     0
				

The sample program below executes in an infinite loop when compiling with /Ox and /4Yb:

Sample Code #2

c FORTRAN Compile options needed: /Ox /4Yb
      J = 0
    1 CONTINUE
      WRITE(*,*) 'Label 1'
      WRITE(*,*) 'J = ', J

      J = J + 1
      IF (J.EQ.2) THEN
     K = 1
      ELSE
     K = 1
      ENDIF

      WRITE(*,*) 'J = ', J
      GOTO(1,2), J        ! Computed GOTO always branches to label 1

    2 CONTINUE
      WRITE(*,*) 'Label 2'
      END