header for now for memset/memcpy opportunities. It turns out that loop-rotate
is successfully rotating loops, but *DOESN'T MERGE THE BLOCKS*, turning "for
loops" into 2 basic block loops that loop-idiom was ignoring.
With this fix, we form many *many* more memcpy and memsets than before, including
on the "history" loops in the viterbi benchmark, which look like this:
for (j=0; j<MAX_history; ++j) {
history_new[i][j+1] = history[2*i][j];
}
Transforming these loops into memcpy's speeds up the viterbi benchmark from
11.98s to 3.55s on my machine. Woo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122685 91177308-0d34-0410-b5e6-96231b3b80d8
compile, and everyone's tests have shown it to be slower in practice, even for
quite large graphs.
I also hope to do an optimization that is only correct with the simpler data
structure, which would break this even further.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122684 91177308-0d34-0410-b5e6-96231b3b80d8
size of a loop header instead of its own code size estimator.
This allows it to handle bitcasts etc more precisely.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122681 91177308-0d34-0410-b5e6-96231b3b80d8
naively implemented, the Lengauer-Tarjan algorithm requires a separate bucket
for each vertex. However, this is unnecessary, because each vertex is only
placed into a single bucket (that of its semidominator), and each vertex's
bucket is processed before it is added to any bucket itself.
Instead of using a bucket per vertex, we use a single array Buckets that has two
purposes. Before the vertex V with DFS number i is processed, Buckets[i] stores
the index of the first element in V's bucket. After V's bucket is processed,
Buckets[i] stores the index of the next element in the bucket to which V now
belongs, if any.
Reading from the buckets can also be optimized. Instead of processing the bucket
of V's parent at the end of processing V, we process the bucket of V itself at
the beginning of processing V. This means that the case of the root vertex can
be simplified somewhat. It also means that we don't need to look up the DFS
number of the semidominator of every node in the bucket we are processing,
since we know it is the current index being processed.
This is a 6.5% speedup running -domtree on test-suite + SPEC2000/2006, with
larger speedups of around 12% on the larger benchmarks like GCC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122680 91177308-0d34-0410-b5e6-96231b3b80d8
maintains the guarantee that the DenseSet expects two elements it contains to
not go from inequal to equal under its nose.
As a side-effect, this also lets us switch from iterating to a fixed-point to
actually maintaining a work queue of functions to look at again, and we don't
add thunks to our work queue so we don't need to detect and ignore them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122677 91177308-0d34-0410-b5e6-96231b3b80d8
limitations, this kicks in dozens of times in the 4 specfp2000 benchmarks,
and hundreds of times in the int part. It also kicks in hundreds of times
in multisource.
This kicks in right before loop deletion, which has the pleasant effect of
deleting loops that *just* do a memset.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122664 91177308-0d34-0410-b5e6-96231b3b80d8
earlyclobber stuff. This should fix PRs 2313 and 8157.
Unfortunately, no testcase, since it'd be dependent on register
assignments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122663 91177308-0d34-0410-b5e6-96231b3b80d8
numbering, in which it considers (for example) "%a = add i32 %x, %y" and
"%b = add i32 %x, %y" to be equal because the operands are equal and the
result of the instructions only depends on the values of the operands.
This has almost no effect (it removes 4 instructions from gcc-as-one-file),
and perhaps slows down compilation: I measured a 0.4% slowdown on the large
gcc-as-one-file testcase, but it wasn't statistically significant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122654 91177308-0d34-0410-b5e6-96231b3b80d8
options. If we are building with exceptions/rtti disabled, we replace
/EHsc with /EHs-c- and /GR with /GR-, respectively. If we just add the
disabling options we get warnings like this:
cl : Command line warning D9025 : overriding '/EHs' with '/EHs-'
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122648 91177308-0d34-0410-b5e6-96231b3b80d8
process those instructions that define phi sources. This is a 47% speedup of
StrongPHIElimination compile time on 403.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122627 91177308-0d34-0410-b5e6-96231b3b80d8
