Fix another place that calls Loop::contains a lot to construct a sorted

container of the blocks and do efficient lookups. This makes
isLoopSimplifyForm much faster on large loops, fixing a significant
compile-time issue in builds with assertions enabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84673 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-10-20 20:41:13 +00:00
parent f7d3570d8e
commit eed9e5b833

View File

@ -292,6 +292,9 @@ bool Loop::isLoopSimplifyForm() const {
// Normal-form loops have a single backedge.
if (!getLoopLatch())
return false;
// Sort the blocks vector so that we can use binary search to do quick
// lookups.
SmallPtrSet<BasicBlock *, 16> LoopBBs(block_begin(), block_end());
// Each predecessor of each exit block of a normal loop is contained
// within the loop.
SmallVector<BasicBlock *, 4> ExitBlocks;
@ -299,7 +302,7 @@ bool Loop::isLoopSimplifyForm() const {
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
for (pred_iterator PI = pred_begin(ExitBlocks[i]),
PE = pred_end(ExitBlocks[i]); PI != PE; ++PI)
if (!contains(*PI))
if (!LoopBBs.count(*PI))
return false;
// All the requirements are met.
return true;