http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29776
sgunderson at bigfoot dot com changed:
What |Removed |Added
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CC| |sgunderson at bigfoot dot com
--- Comment #6 from sgunderson at bigfoot dot com ---
Without knowing anything about the GCC internals here, I could perhaps also
point out that GCC should know that these have limited range. As a trivial
example:
int foo(int x)
{
int z = __builtin_ctz(x);
if (z > 2000) {
return 1;
} else {
return 0;
}
}
There's no way this function can return anything but 0, and VRP should probably
be taught that. (I wonder if this would fix the unneccessary sign extension
too?)
