a function call at the core of the loop inline and removing unused
stack variables from an often called function. This doesn't improve things
much, the real saving will be by reducing the number of calls to this
function (100K+ when linking kimwitu++).
llvm-svn: 19119
1. Calls to external global VARIABLES should not be treated as a call to an
external function
2. Efficiently deleting an element from a vector by using std::swap with
the back, then pop_back is NOT a good way to keep the vector sorted.
3. Our hope of having stuff get deleted by making them redundant just won't
work. In particular, if we have three calls in sequence that should be
merged: A, B, C first we unify B into A. To be sure that they appeared
identical (so B would be erased) we set B = A. On the next step, we
unified C into A and set C = A. Unfortunately, this is no guarantee that
C = B, so we would fail to delete the dead call. Switch to a more
explicit scheme.
llvm-svn: 17357
* change some uses of NH.getNode() in a bool context to use !NH.isNull()
* Fix a bunch of places where we depended on the (undefined) order of
evaluation of arguments to function calls to ensure that getNode() was
called before getOffset(). In practice, this was NOT happening.
llvm-svn: 17354
to go in. This patch allows us to compute the trip count of loops controlled
by values loaded from constant arrays. The cannonnical example of this is
strlen when passed a constant argument:
for (int i = 0; "constantstring"[i]; ++i) ;
return i;
In this case, it will compute that the loop executes 14 times, which means
that the exit value of i is 14. Because of this, the loop gets DCE'd and
we are happy. This also applies to anything that does similar things, e.g.
loops like this:
const float Array[] = { 0.1, 2.1, 3.2, 23.21 };
for (int i = 0; Array[i] < 20; ++i)
and is actually fairly general.
The problem with this is that it almost never triggers. The reason is that
we run indvars and the loop optimizer only at compile time, which is before
things like strlen and strcpy have been inlined into the program from libc.
Because of this, it almost never is used (it triggers twice in specint2k).
I'm committing it because it DOES work, may be useful in the future, and
doesn't slow us down at all. If/when we start running the loop optimizer
at link-time (-O4?) this will be very nice indeed :)
llvm-svn: 16926
Misha Brukman