http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47659
Summary: -Wconversion[-extra] should emit warning for constant
expressions
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: [email protected]
ReportedBy: [email protected]
When the options -Wconversion or -Wconversion-extra are in effect, the compiler
does not generate a warning if a constant real expression is converted to a
different real kind
There should be a warning in this case because the conversion can give
surprising results, e.g.:
real(8) d1, d2
d1 = .13 ! <== no warning
d2 = .13d0
print *, d1, d2, d2-d1
end
Output:
0.12999999523162842 0.13000000000000000 4.76837158647214210E-009
In this case the option -Wconversion-extra should give a warning on "d1 = .13"
because a constant was specified which does not represent the decimal value
with the same precision as the target variable can hold. The user most likely
wanted to specify "d1 = .13d0"
