[Bug c/109542] bad detection of null dereferance cause ud2a in valid inline function code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109542 --- Comment #5 from Jonathan Wakely --- You can either perform the arithmetic using intptr_t or uintptr_t, or use -fdelete-null-pointer-checks (as the documentation for that option explains). Also I would expect a volatile char* to be used for such accesses.
[Bug c/109542] bad detection of null dereferance cause ud2a in valid inline function code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109542 --- Comment #4 from Xi Ruoyao --- (In reply to Amos Maimon from comment #3) > 1. the same will occur if you will do : > p[0xe] = 0xfc; Yes, it's undefined behavior too as C defines a[b] as *(a+b). > 2. how do you explin the fact that if the null set in the function > (SIMPLE_WRITE case) gcc compile it without ud2a It's an undefined behavior, the compiler can do anything.
[Bug c/109542] bad detection of null dereferance cause ud2a in valid inline function code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109542 --- Comment #3 from Amos Maimon --- 1. the same will occur if you will do : p[0xe] = 0xfc; 2. how do you explin the fact that if the null set in the function (SIMPLE_WRITE case) gcc compile it without ud2a
[Bug c/109542] bad detection of null dereferance cause ud2a in valid inline function code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109542 Richard Biener changed: What|Removed |Added Target||x86_64-*-* i?86-*-* Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED --- Comment #2 from Richard Biener --- This works exactly as intended. In C when you offset a pointer you may not venture outside of a valid object and at NULL there isn't a valid object unless -fno-delete-null-pointer-checks.
[Bug c/109542] bad detection of null dereferance cause ud2a in valid inline function code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109542 Xi Ruoyao changed: What|Removed |Added CC||xry111 at gcc dot gnu.org --- Comment #1 from Xi Ruoyao --- Performing arithmetic on NULL pointer is an undefined behavior. The standard says you can only perform arithmetic on a pointer if it's a pointer to an array element (an object not in any array will be considered as the only element in an array with length 1), but NULL is not such a pointer.
