This patch adds a -Wconversion warning (enabled also by -Wall) for
CMPLX(real, real)
if the real arguments have a higher kind number/precision as the
default-kind of complex/real. I think most of the time, this precision
loss is unintended; it can be silenced when using a kind= parameter (or
-Wno-conversion).
However, if you believe that the warning is not suitable for -Wall, we
can also hide it by only enabling it with the talkative
-Wconversion-extra flag.
Build and regtested on x86-64-linux.
OK for the trunk?
Tobias
2012-08-14 Tobias Burnus <bur...@net-b.de>
PR fortran/54234
* check.c (gfc_check_cmplx): Add -Wconversion warning
when converting higher-precision REAL to default-precision
CMPLX without kind= parameter.
2012-08-14 Tobias Burnus <bur...@net-b.de>
PR fortran/54234
* gfortran.dg/warn_conversion_4.f90: New.
diff --git a/gcc/fortran/check.c b/gcc/fortran/check.c
index c5bf79b..2235b52 100644
--- a/gcc/fortran/check.c
+++ b/gcc/fortran/check.c
@@ -1278,6 +1278,17 @@ gfc_check_cmplx (gfc_expr *x, gfc_expr *y, gfc_expr *kind)
if (kind_check (kind, 2, BT_COMPLEX) == FAILURE)
return FAILURE;
+ if (!kind && gfc_option.gfc_warn_conversion
+ && x->ts.type == BT_REAL && x->ts.kind > gfc_default_real_kind)
+ gfc_warning_now ("Conversion from %s to default-kind COMPLEX(%d) at %L "
+ "might loose precision, consider using the KIND argument",
+ gfc_typename (&x->ts), gfc_default_real_kind, &x->where);
+ else if (y && !kind && gfc_option.gfc_warn_conversion
+ && y->ts.type == BT_REAL && y->ts.kind > gfc_default_real_kind)
+ gfc_warning_now ("Conversion from %s to default-kind COMPLEX(%d) at %L "
+ "might loose precision, consider using the KIND argument",
+ gfc_typename (&y->ts), gfc_default_real_kind, &y->where);
+
return SUCCESS;
}
--- /dev/null 2012-08-08 07:41:43.631684108 +0200
+++ gcc/gcc/testsuite/gfortran.dg/warn_conversion_4.f90 2012-08-14 10:19:56.000000000 +0200
@@ -0,0 +1,18 @@
+! { dg-do compile }
+! { dg-options "-Wconversion" }
+!
+! PR fortran/54234
+!
+!
+module fft_mod
+ implicit none
+ integer, parameter :: dp=kind(0.0d0)
+contains
+ subroutine test
+ integer :: x
+ x = int (abs (cmplx(2.3,0.1)))
+ x = int (abs (cmplx(2.3_dp,0.1))) ! { dg-warning "Conversion from REAL.8. to default-kind COMPLEX.4. at .1. might loose precision, consider using the KIND argument" }
+ x = int (abs (cmplx(2.3,0.1_dp))) ! { dg-warning "Conversion from REAL.8. to default-kind COMPLEX.4. at .1. might loose precision, consider using the KIND argument" }
+ x = int (abs (cmplx(2.3_dp,0.1_dp))) ! { dg-warning "Conversion from REAL.8. to default-kind COMPLEX.4. at .1. might loose precision, consider using the KIND argument" }
+ end subroutine test
+end module fft_mod
--- /dev/null 2012-08-08 07:41:43.631684108 +0200
+++ gcc/gcc/testsuite/gfortran.dg/warn_conversion_4.f90 2012-08-14 10:19:56.000000000 +0200
@@ -0,0 +1,18 @@
+! { dg-do compile }
+! { dg-options "-Wconversion" }
+!
+! PR fortran/54234
+!
+!
+module fft_mod
+ implicit none
+ integer, parameter :: dp=kind(0.0d0)
+contains
+ subroutine test
+ integer :: x
+ x = int (abs (cmplx(2.3,0.1)))
+ x = int (abs (cmplx(2.3_dp,0.1))) ! { dg-warning "Conversion from REAL.8. to default-kind COMPLEX.4. at .1. might loose precision, consider using the KIND argument" }
+ x = int (abs (cmplx(2.3,0.1_dp))) ! { dg-warning "Conversion from REAL.8. to default-kind COMPLEX.4. at .1. might loose precision, consider using the KIND argument" }
+ x = int (abs (cmplx(2.3_dp,0.1_dp))) ! { dg-warning "Conversion from REAL.8. to default-kind COMPLEX.4. at .1. might loose precision, consider using the KIND argument" }
+ end subroutine test
+end module fft_mod
