http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53001
--- Comment #11 from Joshua Cogliati <jjcogliati-r1 at yahoo dot com> --- Created attachment 30873 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30873&action=edit Patch to add -Wfloat-conversion option This version also is enabled with -Wextra. $ gcc -o float_test float_test.c $ gcc -Wfloat-conversion -o float_test float_test.c float_test.c: In function ‘main’: float_test.c:2:3: warning: conversion to ‘int’ alters ‘double’ constant value [-Wfloat-conversion] int i = 3.14; ^ float_test.c: In function ‘foo’: float_test.c:8:3: warning: conversion to ‘int’ from ‘double’ may alter its value [-Wfloat-conversion] return x; ^ float_test.c: In function ‘foo2’: float_test.c:12:3: warning: conversion to ‘float’ from ‘double’ may alter its value [-Wfloat-conversion] return x; ^ $ gcc -Wconversion -o float_test float_test.c float_test.c: In function ‘main’: float_test.c:2:3: warning: conversion to ‘int’ alters ‘double’ constant value [-Wfloat-conversion] int i = 3.14; ^ float_test.c: In function ‘foo’: float_test.c:8:3: warning: conversion to ‘int’ from ‘double’ may alter its value [-Wfloat-conversion] return x; ^ float_test.c: In function ‘foo2’: float_test.c:12:3: warning: conversion to ‘float’ from ‘double’ may alter its value [-Wfloat-conversion] return x; ^ $ gcc -Wextra -o float_test float_test.c float_test.c: In function ‘main’: float_test.c:2:3: warning: conversion to ‘int’ alters ‘double’ constant value [-Wfloat-conversion] int i = 3.14; ^ float_test.c: In function ‘foo’: float_test.c:8:3: warning: conversion to ‘int’ from ‘double’ may alter its value [-Wfloat-conversion] return x; ^ float_test.c: In function ‘foo2’: float_test.c:12:3: warning: conversion to ‘float’ from ‘double’ may alter its value [-Wfloat-conversion] return x; ^