warning: conversion from ‘int’ to ‘char’ may change value

[Umesh Kalappa]

Hi All,

When we try to compile the below case from trunk gcc we get the below
warning (-Wconversion) i.e

void start(void) {
 char n = 1;
 char n1 = 0x01;
 n &=  ~n1;
}

$xgcc -S  warn.c -nostdinc -Wconversion
 warning: conversion from ‘int’ to ‘char’ may change value [-Wconversion]
  n &=  ~n1;

typecast the expression like "n& = (char)~n1" and warning goes away .

and when we investigated the gcc source and warning coming from
unsafe_conversion_p@ gcc/c-family/c-common.c:1226

if (TYPE_PRECISION (type) < TYPE_PRECISION (expr_type))
give_warning = UNSAFE_OTHER;

where TYPE_PRECISION (type) is 8  for char and TYPE_PRECISION
(expr_type) is 32  as expected for int .

is that expected behavior of gcc ?

clang compiles with no warnings .

Thank you
~Umesh