False Positive because if() is not processed correctly?

[Absinthe Sautereau]

I have come across this problem that seems like cppcheck just isn't understanding the flow of the if statement. It is showing that memset is getting a -1 value but that else statement should never be accessed for the case when src is > tgt. Obviously this code is a reduced variation of what is actually going on. But it seems to be the smallest piece of code that demonstrates the behavior.

#include <stdio.h>
#include <string.h>

int main (void) {

    char tgt[7];
    char src[7+1] = "7777777";

    if (sizeof tgt <= sizeof src) { 
        memmove(&tgt, &src, sizeof tgt); 
    } else { 
        memmove(&tgt, &src, sizeof src); 
        memset(&tgt + sizeof src, ' ', sizeof tgt - sizeof src); 
    }

    return 0;
}

main.c;13;error;invalidFunctionArg;Invalid memset() argument nr 3. The value is -1 but the valid values are '0:'. 

[CHR]

I can reproduce this with v2.3.

[CHR]

I have created a ticket: https://trac.cppcheck.net/ticket/10157