false positive in comparison with cast

[llvmbot]

Bugzilla Link	10721
Version	trunk
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@tkremenek

Extended Description

clang version 3.0 (trunk 138324)
Target: x86_64-unknown-linux-gnu

Running this through the static analyser:

struct S { unsigned long long x; };
int f(struct S *p) {
if (p->x != (unsigned)p->x)
return 1;
else
return 2;
}

yields the warning:

clangbug.c:3:14: warning: Both operands to '!=' always have the same value
if (p->x != (unsigned)p->x)
~~~~ ^ ~~~~~~~~~~~~~~

[llvmbot]

assigned to @tkremenek

[tkremenek]

This is a result of the unsound way we handle integer casts.

[tkremenek]

cloned to rdar://problem/10010006