replaced by a bigger array in SmallPtrSet (by overridding it), instead just use a
pointer to the start of the storage, and have SmallPtrSet pass in the value to use.
This has the disadvantage that SmallPtrSet becomes bigger by one pointer. It has
the advantage that it no longer uses tricky C++ rules, and is clearly correct while
I'm not sure the previous version was. This was inspired by g++-4.6 pointing out
that SmallPtrSetImpl was writing off the end of SmallArray, which it was. Since
SmallArray is replaced with a bigger array in SmallPtrSet, the write was still to
valid memory. But it was writing off the end of the declared array type - sounds
kind of dubious to me, like it sounded dubious to g++-4.6. Maybe g++-4.6 is wrong
and this construct is perfectly valid and correctly compiled by all compilers, but
I think it is better to avoid the whole can of worms by avoiding this construct.
llvm-svn: 107285
SmallArray[SmallSize] in the SmallPtrSetIteratorImpl, and this is
one off the end of the array. For those who care, right now gcc
warns about writing off the end because it is confused about the
declaration of SmallArray as having length 1 in the parent class
SmallPtrSetIteratorImpl. However if you tweak code to unconfuse
it, then it still warns about writing off the end of the array,
because of this buffer overflow. In short, even with this fix
gcc-4.6 will warn about writing off the end of the array, but now
that is only because it is confused.
llvm-svn: 107200
contents of the set were small, deallocate and shrink the set. This
avoids having us to memset as much data, significantly speeding up
some pathological cases. For example, this speeds up the verifier
from 0.3899s to 0.0763 (5.1x) on the testcase from PR1432 in a
release build.
llvm-svn: 40837
