RPCS3/llvm
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm.git synced 2025-01-09 13:41:47 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[Analysis] Print out unreachable loops

Browse Source 
Summary:
When writing a loop pass I made a mistake and hit the assertion
"Unreachable block in loop". Later, I hit an assertion when I called
`BasicBlock::eraseFromParent()` incorrectly: "Use still stuck around
after Def is destroyed". This latter assertion, however, printed out
exactly which value is being deleted and what uses remain, which helped
me debug the issue.

To help people debugging their loop passes in the future, print out
exactly which basic block is unreachable in a loop.

Reviewers: sanjoy, hfinkel, mehdi_amini

Reviewed By: mehdi_amini

Subscribers: mzolotukhin

Differential Revision: https://reviews.llvm.org/D32878

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302354 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Brian Gesiak 2017-05-06 16:22:53 +00:00
parent 88a4e3bee5
commit 8a886c7975
1 changed files with 12 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/llvm/Analysis/LoopInfoImpl.h
View File

@ -220,8 +220,8 @@ void LoopBase<BlockT, LoopT>::verifyLoop() const {
BI = df_ext_begin(getHeader(), VisitSet),
BE = df_ext_end(getHeader(), VisitSet);
// Keep track of the number of BBs visited.
unsigned NumVisited = 0;
// Keep track of the BBs visited.
SmallPtrSet<BlockT*, 8> VisitedBBs;
// Check the individual blocks.
for ( ; BI != BE; ++BI) {
@ -259,10 +259,18 @@ void LoopBase<BlockT, LoopT>::verifyLoop() const {
assert(BB != &getHeader()->getParent()->front() &&
"Loop contains function entry block!");
NumVisited++;
VisitedBBs.insert(BB);
}
assert(NumVisited == getNumBlocks() && "Unreachable block in loop");
if (VisitedBBs.size() != getNumBlocks()) {
dbgs() << "The following blocks are unreachable in the loop: ";
for (auto BB : Blocks) {
if (!VisitedBBs.count(BB)) {
dbgs() << *BB << "\n";
}
}
assert(false && "Unreachable block in loop");
}
// Check the subloops.
for (iterator I = begin(), E = end(); I != E; ++I)