Hello world,
the attached patch warns about comparisions for equality and inequality
of real and complex values if -Wcompare-reals is given. The new
compiler option is included in -Wall.
Regression-tested, tested with "make info" and "make dvi".
OK for trunk?
Thomas
2012-08-19 Thomas König <tkoe...@gcc.gnu.org>
PR fortran/54298
* gfortran.h (struct gfc_option_t): Add warn_compare_reals.
* lang.opt: Add Wcompare-reals.
* invoke.texi: Document -Wcompare-reals.
* resolve.c (resolve_operator): If -Wcompare-reals is in effect,
warn about equality/inequality comparisions for REAL and COMPLEX.
* options.c (gfc_init_options): Set warn_compare_reals.
(set_Wall): Include warn_compare_reals in Wall.
(gfc_handle_option): Handle Wcompare_reals.
2012-08-19 Thomas König <tkoe...@gcc.gnu.org>
PR fortran/54298
* gfortran.dg/real_compare_1.f90: New test case.
* gfortran.dg/bessel_5.f90 Add -Wno-compare-reals to options.
Index: testsuite/gfortran.dg/bessel_5.f90
===================================================================
--- testsuite/gfortran.dg/bessel_5.f90 (Revision 190442)
+++ testsuite/gfortran.dg/bessel_5.f90 (Arbeitskopie)
@@ -1,5 +1,5 @@
! { dg-do run }
-! { dg-options "-Wall -fno-range-check" }
+! { dg-options "-Wall -fno-range-check -Wno-compare-reals" }
!
! PR fortran/36158 - Transformational BESSEL_JN/YN
! PR fortran/33197 - F2008 math functions
Index: fortran/gfortran.h
===================================================================
--- fortran/gfortran.h (Revision 190442)
+++ fortran/gfortran.h (Arbeitskopie)
@@ -2225,6 +2225,7 @@ typedef struct
int warn_unused_dummy_argument;
int warn_realloc_lhs;
int warn_realloc_lhs_all;
+ int warn_compare_reals;
int max_errors;
int flag_all_intrinsics;
Index: fortran/lang.opt
===================================================================
--- fortran/lang.opt (Revision 190442)
+++ fortran/lang.opt (Arbeitskopie)
@@ -218,6 +218,10 @@ Wcharacter-truncation
Fortran Warning
Warn about truncated character expressions
+Wcompare-reals
+Fortran Warning
+Warn about equality comparisons involving REAL or COMPLEX expressions
+
Wconversion
Fortran Warning
; Documented in C
Index: fortran/invoke.texi
===================================================================
--- fortran/invoke.texi (Revision 190442)
+++ fortran/invoke.texi (Arbeitskopie)
@@ -726,10 +726,11 @@ warnings.
@cindex warnings, all
Enables commonly used warning options pertaining to usage that
we recommend avoiding and that we believe are easy to avoid.
-This currently includes @option{-Waliasing}, @option{-Wampersand},
-@option{-Wconversion}, @option{-Wsurprising}, @option{-Wintrinsics-std},
-@option{-Wno-tabs}, @option{-Wintrinsic-shadow}, @option{-Wline-truncation},
-@option{-Wreal-q-constant} and @option{-Wunused}.
+This currently includes @option{-Waliasing}, @option{-Wampersand},
+@option{-Wconversion}, @option{-Wcompare-reals}, @option{-Wsurprising},
+@option{-Wintrinsics-std}, @option{-Wno-tabs}, @option{-Wintrinsic-shadow},
+@option{-Wline-truncation}, @option{-Wreal-q-constant} and
+@option{-Wunused}.
@item -Waliasing
@opindex @code{Waliasing}
@@ -935,6 +936,11 @@ a scalar. See also @option{-frealloc-lhs}.
Warn when the compiler inserts code to for allocation or reallocation of an
allocatable variable; this includes scalars and derived types.
+@item -Wcompare-reals
+@opindex @code{Wcompare-reals}
+Warn when comparing real or complex types for equality or inequality.
+Enabled by @option{-Wall}.
+
@item -Werror
@opindex @code{Werror}
@cindex warnings, to errors
Index: fortran/resolve.c
===================================================================
--- fortran/resolve.c (Revision 190442)
+++ fortran/resolve.c (Arbeitskopie)
@@ -4034,6 +4034,27 @@ resolve_operator (gfc_expr *e)
e->ts.type = BT_LOGICAL;
e->ts.kind = gfc_default_logical_kind;
+
+ if (gfc_option.warn_compare_reals)
+ {
+ gfc_intrinsic_op op = e->value.op.op;
+
+ if ((op1->ts.type == BT_REAL || op1->ts.type == BT_COMPLEX)
+ && (op == INTRINSIC_EQ || op == INTRINSIC_EQ_OS
+ || op == INTRINSIC_NE || op == INTRINSIC_NE_OS))
+ {
+ bool equality;
+
+ equality = op == INTRINSIC_EQ || op == INTRINSIC_EQ_OS;
+
+ /* Type conversion has made sure that the types
+ of op1 and op2 agree. */
+ gfc_warning ("%s comparison for %s at %L",
+ equality ? "Equality" : "Inequality",
+ gfc_typename (&op1->ts), &op1->where);
+ }
+ }
+
break;
}
Index: fortran/options.c
===================================================================
--- fortran/options.c (Revision 190442)
+++ fortran/options.c (Arbeitskopie)
@@ -113,6 +113,7 @@ gfc_init_options (unsigned int decoded_options_cou
gfc_option.warn_unused_dummy_argument = 0;
gfc_option.warn_realloc_lhs = 0;
gfc_option.warn_realloc_lhs_all = 0;
+ gfc_option.warn_compare_reals = 0;
gfc_option.max_errors = 25;
gfc_option.flag_all_intrinsics = 0;
@@ -473,6 +474,7 @@ set_Wall (int setting)
gfc_option.warn_character_truncation = setting;
gfc_option.warn_real_q_constant = setting;
gfc_option.warn_unused_dummy_argument = setting;
+ gfc_option.warn_compare_reals = setting;
warn_return_type = setting;
warn_switch = setting;
@@ -638,6 +640,10 @@ gfc_handle_option (size_t scode, const char *arg,
gfc_option.warn_character_truncation = value;
break;
+ case OPT_Wcompare_reals:
+ gfc_option.warn_compare_reals = value;
+ break;
+
case OPT_Wconversion:
gfc_option.gfc_warn_conversion = value;
break;
! { dg-do compile }
! { dg-options "-Wcompare-reals" }
program main
real :: a
complex :: c
read (*,*) a
read (*,*) c
if (a .eq. 3.14) print *,"foo" ! { dg-warning "Equality comparison for REAL" }
if (3.14 == a) print *,"foo" ! { dg-warning "Equality comparison for REAL" }
if (a .eq. 3) print *,"foo" ! { dg-warning "Equality comparison for REAL" }
if (3. == a) print *,"foo" ! { dg-warning "Equality comparison for REAL" }
if (a .ne. 4.14) print *,"foo" ! { dg-warning "Inequality comparison for REAL" }
if (4.14 /= a) print *,"foo" ! { dg-warning "Inequality comparison for REAL" }
if (a .ne. 4) print *,"foo" ! { dg-warning "Inequality comparison for REAL" }
if (4 /= a) print *,"foo" ! { dg-warning "Inequality comparison for REAL" }
if (c .eq. (3.14, 2.11)) print *,"foo" ! { dg-warning "Equality comparison for COMPLEX" }
if ((3.14, 2.11) == a) print *,"foo" ! { dg-warning "Equality comparison for COMPLEX" }
if (c .ne. (3.14, 2.11)) print *,"foo" ! { dg-warning "Inequality comparison for COMPLEX" }
if ((3.14, 2.11) /= a) print *,"foo" ! { dg-warning "Inequality comparison for COMPLEX" }
end program main
