From 5e93a7672222853cdf5dd261c322e6f89d40be01 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Sun, 8 Apr 2012 14:37:02 +0000
Subject: [PATCH] Remove an over zealous assert. The assert was trying to catch
places where a chain outside of the loop block-set ended up in the worklist
for scheduling as part of the contiguous loop. However, asserting the first
block in the chain is in the loop-set isn't a valid check -- we may be forced
to drag a chain into the worklist due to one block in the chain being part of
the loop even though the first block is *not* in the loop. This occurs when
we have been forced to form a chain early due to un-analyzable branches.
No test case here as I have no idea how to even begin reducing one, and
it will be hopelessly fragile. We have to somehow end up with a loop
header of an inner loop which is a successor of a basic block with an
unanalyzable pair of branch instructions. Ow. Self-host triggers it so
it is unlikely it will regress.
This at least gets block placement back to passing selfhost and the test
suite. There are still a lot of slowdown that I don't like coming out of
block placement, although there are now also a lot of speedups. =[ I'm
seeing swings in both directions up to 10%. I'm going to try to find
time to dig into this and see if we can turn this on for 3.1 as it does
a really good job of cleaning up after some loops that degraded with the
inliner changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154287 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/CodeGen/MachineBlockPlacement.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp
index 07b7318ef2e..52fde7f44b9 100644
--- a/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/lib/CodeGen/MachineBlockPlacement.cpp
@@ -438,7 +438,6 @@ MachineBasicBlock *MachineBlockPlacement::selectBestCandidateBlock(
for (SmallVectorImpl<MachineBasicBlock *>::iterator WBI = WorkList.begin(),
WBE = WorkList.end();
WBI != WBE; ++WBI) {
- assert(!BlockFilter || BlockFilter->count(*WBI));
BlockChain &SuccChain = *BlockToChain[*WBI];
if (&SuccChain == &Chain) {
DEBUG(dbgs() << " " << getBlockName(*WBI)