[PartialInliner] Fix crash when inlining functions with unreachable blocks.
CodeExtractor looks up the dominator node corresponding to return blocks
when splitting them. If one of these blocks is unreachable, there's no
node in the Dom and CodeExtractor crashes because it doesn't check
for domtree node validity.
In theory, we could add just a check for skipping null DTNodes in
`splitReturnBlock` but the fix I propose here is slightly different. To the
best of my knowledge, unreachable blocks are irrelevant for the algorithm,
therefore we can just skip them when building the candidate set in the
constructor.
Differential Revision: https://reviews.llvm.org/D32335
llvm-svn: 300946
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 92b6c0b..5a1b892 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -74,24 +74,25 @@
/// \brief Build a set of blocks to extract if the input blocks are viable.
static SetVector<BasicBlock *>
-buildExtractionBlockSet(ArrayRef<BasicBlock *> BBs) {
- auto BBBegin = BBs.begin();
- auto BBEnd = BBs.end();
- assert(BBBegin != BBEnd && "The set of blocks to extract must be non-empty");
-
+buildExtractionBlockSet(ArrayRef<BasicBlock *> BBs, DominatorTree *DT) {
+ assert(!BBs.empty() && "The set of blocks to extract must be non-empty");
SetVector<BasicBlock *> Result;
// Loop over the blocks, adding them to our set-vector, and aborting with an
// empty set if we encounter invalid blocks.
- do {
- if (!Result.insert(*BBBegin))
- llvm_unreachable("Repeated basic blocks in extraction input");
+ for (BasicBlock *BB : BBs) {
- if (!CodeExtractor::isBlockValidForExtraction(**BBBegin)) {
+ // If this block is dead, don't process it.
+ if (DT && !DT->isReachableFromEntry(BB))
+ continue;
+
+ if (!Result.insert(BB))
+ llvm_unreachable("Repeated basic blocks in extraction input");
+ if (!CodeExtractor::isBlockValidForExtraction(*BB)) {
Result.clear();
return Result;
}
- } while (++BBBegin != BBEnd);
+ }
#ifndef NDEBUG
for (SetVector<BasicBlock *>::iterator I = std::next(Result.begin()),
@@ -111,13 +112,13 @@
bool AggregateArgs, BlockFrequencyInfo *BFI,
BranchProbabilityInfo *BPI)
: DT(DT), AggregateArgs(AggregateArgs || AggregateArgsOpt), BFI(BFI),
- BPI(BPI), Blocks(buildExtractionBlockSet(BBs)), NumExitBlocks(~0U) {}
+ BPI(BPI), Blocks(buildExtractionBlockSet(BBs, DT)), NumExitBlocks(~0U) {}
CodeExtractor::CodeExtractor(DominatorTree &DT, Loop &L, bool AggregateArgs,
BlockFrequencyInfo *BFI,
BranchProbabilityInfo *BPI)
: DT(&DT), AggregateArgs(AggregateArgs || AggregateArgsOpt), BFI(BFI),
- BPI(BPI), Blocks(buildExtractionBlockSet(L.getBlocks())),
+ BPI(BPI), Blocks(buildExtractionBlockSet(L.getBlocks(), &DT)),
NumExitBlocks(~0U) {}
/// definedInRegion - Return true if the specified value is defined in the