strlen0.f: New test.

2001-09-22  George Helffrich  <george@geo.titech.ac.jp>

	* g77.dg/strlen0.f: New test.

From-SVN: r45748

gcc/testsuite/ChangeLog

+2001-09-22  George Helffrich  <george@geo.titech.ac.jp>
+
+	* g77.dg/strlen0.f: New test.
+
 2001-09-21  Richard Henderson  <rth@redhat.com>
 
 	* g++.old-deja/g++.abi/ptrmem.C: Update for ia64 c++ abi.

gcc/testsuite/g77.dg/strlen0.f

+C     Substring range checking test program, to check behavior with respect
+C     to X3J3/90.4 paragraph 5.7.1.
+C
+C     Patches relax substring checking for subscript expressions in order to
+C     simplify coding (elimination of length checks for strings passed as
+C     parameters) and to avoid contradictory behavior of subscripted substring
+C     expressions with respect to unsubscripted string expressions.
+C
+C     Key part of 5.7.1 interpretation comes down to statement that in the
+C     substring expression,
+C        v ( e1 : e2 )
+C     1 <= e1 <= e2 <= len to be valid, yet the expression
+C        v ( : )
+C     is equivalent to
+C        v(1:len(v))
+C
+C     meaning that any statement that reads
+C        str = v // 'tail'
+C     (where v is a string passed as a parameter) would require coding as
+C        if (len(v) .gt. 0) then
+C           str = v // 'tail'
+C        else
+C           str = 'tail'
+C        endif
+C     to comply with the standard specification.  Under the stricter
+C     interpretation, functions strcat and strlat would be incorrect as
+C     written for null values of str1 and/or str2.
+C
+C     This code compiles and runs without error on
+C       SunOS 4.1.3 f77 (-C option)
+C       SUNWspro SparcCompiler 4.2 f77 (-C option)
+C       (and with proposed patches, gcc-2.9.2 -fbounds-check except for test 6,
+C        which is a genuine, deliberate error - comment out to make further
+C        tests)
+C
+C { dg-do run }
+C { dg-options "-fbounds-check" }
+C
+C     G. Helffrich/Tokyo Inst. Technology Jul 24 2001
+
+      character str*8,strres*16,strfun*16,strcat*16,strlat*16
+
+      str='Hi there'
+
+C     Test 1 - (current+patched) two char substring result
+      strres=strfun(str,1,2)
+      write(*,*) 'strres is ',strres
+
+C     Test 2 - (current+patched) null string result
+      strres=strfun(str,5,4)
+      write(*,*) 'strres is ',strres
+
+C     Test 3 - (current+patched) null string result
+      strres=strfun(str,8,7)
+      write(*,*) 'strres is ',strres
+
+C     Test 4 - (current) error; (patched) null string result
+      strres=strfun(str,9,8)
+      write(*,*) 'strres is ',strres
+
+C     Test 5 - (current) error; (patched) null string result
+      strres=strfun(str,1,0)
+      write(*,*) 'strres is ',strres
+
+C     Test 6 - (current+patched) error
+C     strres=strfun(str,20,20)
+C     write(*,*) 'strres is ',strres
+
+C     Test 7 - (current+patched) str result
+      strres=strcat(str,'')
+      write(*,*) 'strres is ',strres
+
+C     Test 8 - (current) error; (patched) str result
+      strres=strlat('',str)
+      write(*,*) 'strres is ',strres
+
+      end
+
+      character*(*) function strfun(str,i,j)
+      character str*(*)
+
+      strfun = str(i:j)
+      end
+
+      character*(*) function strcat(str1,str2)
+      character str1*(*), str2*(*)
+
+      strcat = str1 // str2
+      end
+
+      character*(*) function strlat(str1,str2)
+      character str1*(*), str2*(*)
+
+      strlat = str1(1:len(str1)) // str2(1:len(str2))
+      end