http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
--- Comment #3 from Steve Kargl sgk at troutmask dot apl.washington.edu
2011-09-28 19:45:48 UTC ---
On Wed, Sep 28, 2011 at 09:20:40AM +, zeccav at gmail dot com wrote:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
--- Comment #2 from Vittorio Zecca zeccav at gmail dot com 2011-09-28
09:20:40 UTC ---
I meant checking static expressions at compilation time, as in my example.
This has no cost at run time.
I know want you meant.
You proposed a run time check that still should be done if requested with a
kind of -fcheck option.
I disagree.
By the way, gfortran is already checking consistency of static arguments to
intrinsic functions, it is that just these one are left unchecked.
Yes, I know. I wrote some of the code.
Index: testsuite/gfortran.dg/ishft_3.f90
===
--- testsuite/gfortran.dg/ishft_3.f90(revision 179208)
+++ testsuite/gfortran.dg/ishft_3.f90(working copy)
@@ -1,11 +1,38 @@
! { dg-do compile }
+! PR fortran/50514
program ishft_3
- integer i, j
- write(*,*) ishftc( 3, 2, 3 )
- write(*,*) ishftc( 3, 2, i )
- write(*,*) ishftc( 3, i, j )
- write(*,*) ishftc( 3, 128 ) ! { dg-error exceeds BIT_SIZE of first }
- write(*,*) ishftc( 3, 0, 128 ) ! { dg-error exceeds BIT_SIZE of first }
- write(*,*) ishftc( 3, 0, 0 )! { dg-error Invalid third argument }
- write(*,*) ishftc( 3, 3, 2 )! { dg-error exceeds third argument }
+
+ implicit none
+
+ integer j, m
+
+ m = 42
+ !
+ ! These should compile.
+ !
+ j = ishft(m, 16)
+ j = ishft(m, -16)
+ j = ishftc(m, 16)
+ j = ishftc(m, -16)
+ !
+ ! These should issue an error.
+ !
+ j = ishft(m, 640)! { dg-error absolute value of SHIFT }
+ j = ishftc(m, 640) ! { dg-error absolute value of SHIFT }
+ j = ishft(m, -640) ! { dg-error absolute value of SHIFT }
+ j = ishftc(m, -640) ! { dg-error absolute value of SHIFT }
+
+ ! abs(SHIFT) must be = SIZE
+
+ j = ishftc(m, 1, 2)
+ j = ishftc(m, 1, 2)
+ j = ishftc(m, -1, 2)
+ j = ishftc(m, -1, 2)
+
+ j = ishftc(m, 10, 2)! { dg-error absolute value of SHIFT }
+ j = ishftc(m, 10, 2)! { dg-error absolute value of SHIFT }
+ j = ishftc(m, -10, 2)! { dg-error absolute value of SHIFT }
+ j = ishftc(m, -10, 2)! { dg-error absolute value of SHIFT }
+
+ j = ishftc(m, 1, -2) ! { dg-error must be positive }
end program
Index: fortran/check.c
===
--- fortran/check.c(revision 179208)
+++ fortran/check.c(working copy)
@@ -318,6 +318,22 @@ less_than_bitsize1 (const char *arg1, gf
{
gfc_extract_int (expr2, i2);
i3 = gfc_validate_kind (BT_INTEGER, expr1-ts.kind, false);
+
+ /* For ISHFT[C], |shift| = bit_size(i). */
+ if (strncmp (arg2, ISHFT, 5) == 0)
+{
+ if (i2 0)
+i2 = -i2;
+
+ if (i2 gfc_integer_kinds[i3].bit_size)
+{
+ gfc_error (The absolute value of SHIFT at %L must be less
+ than or equal to BIT_SIZE('%s'),
+ expr2-where, arg1);
+ return FAILURE;
+}
+}
+
if (or_equal)
{
if (i2 gfc_integer_kinds[i3].bit_size)
@@ -1961,6 +1977,9 @@ gfc_check_ishft (gfc_expr *i, gfc_expr *
|| type_check (shift, 1, BT_INTEGER) == FAILURE)
return FAILURE;
+ if (less_than_bitsize1 (I, i, ISHFT, shift, true) == FAILURE)
+return FAILURE;
+
return SUCCESS;
}
@@ -1972,7 +1991,35 @@ gfc_check_ishftc (gfc_expr *i, gfc_expr
|| type_check (shift, 1, BT_INTEGER) == FAILURE)
return FAILURE;
- if (size != NULL type_check (size, 2, BT_INTEGER) == FAILURE)
+ if (size != NULL)
+{
+ int i2, i3;
+
+ if (type_check (size, 2, BT_INTEGER) == FAILURE)
+return FAILURE;
+
+ if (less_than_bitsize1 (I, i, SIZE, size, true) == FAILURE)
+return FAILURE;
+
+ gfc_extract_int (size, i3);
+ if (i3 = 0)
+{
+ gfc_error (SIZE at %L must be positive, size-where);
+ return FAILURE;
+}
+
+ gfc_extract_int (shift, i2);
+ if (i2 0)
+i2 = -i2;
+
+ if (i2 i3)
+{
+ gfc_error (The absolute value of SHIFT at %L must be less than
+ or equal to SIZE at %L, shift-where, size-where);
+ return FAILURE;
+}
+}
+ else if (less_than_bitsize1 (I, i, ISHFTC, shift, true) == FAILURE)
return FAILURE;
return SUCCESS;
