Fix dominator descendants for unreachable blocks.
When a block is unreachable, asking its dom tree descendants should
return the empty set. However, the computation of the descendants
was causing a segmentation fault because the dom tree node we get
from the basic block is initially NULL.
Fixed by adding a test for a valid dom tree node before we iterate.
The patch also adds some unit tests to the existing dom tree tests.
llvm-svn: 196099
diff --git a/llvm/unittests/IR/DominatorTreeTest.cpp b/llvm/unittests/IR/DominatorTreeTest.cpp
index 4e5af93..387d732 100644
--- a/llvm/unittests/IR/DominatorTreeTest.cpp
+++ b/llvm/unittests/IR/DominatorTreeTest.cpp
@@ -8,6 +8,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/PostDominators.h"
#include "llvm/Assembly/Parser.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
@@ -26,6 +27,7 @@
static char ID;
virtual bool runOnFunction(Function &F) {
DominatorTree *DT = &getAnalysis<DominatorTree>();
+ PostDominatorTree *PDT = &getAnalysis<PostDominatorTree>();
Function::iterator FI = F.begin();
BasicBlock *BB0 = FI++;
@@ -148,10 +150,34 @@
EXPECT_TRUE(DT->dominates(Y6, BB3));
+ // Post dominance.
+ EXPECT_TRUE(PDT->dominates(BB0, BB0));
+ EXPECT_FALSE(PDT->dominates(BB1, BB0));
+ EXPECT_FALSE(PDT->dominates(BB2, BB0));
+ EXPECT_FALSE(PDT->dominates(BB3, BB0));
+ EXPECT_TRUE(PDT->dominates(BB4, BB1));
+
+ // Dominance descendants.
+ SmallVector<BasicBlock *, 8> DominatedBBs, PostDominatedBBs;
+
+ DT->getDescendants(BB0, DominatedBBs);
+ PDT->getDescendants(BB0, PostDominatedBBs);
+ EXPECT_EQ(DominatedBBs.size(), 4UL);
+ EXPECT_EQ(PostDominatedBBs.size(), 1UL);
+
+ // BB3 is unreachable. It should have no dominators nor postdominators.
+ DominatedBBs.clear();
+ PostDominatedBBs.clear();
+ DT->getDescendants(BB3, DominatedBBs);
+ DT->getDescendants(BB3, PostDominatedBBs);
+ EXPECT_EQ(DominatedBBs.size(), 0UL);
+ EXPECT_EQ(PostDominatedBBs.size(), 0UL);
+
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<DominatorTree>();
+ AU.addRequired<PostDominatorTree>();
}
DPass() : FunctionPass(ID) {
initializeDPassPass(*PassRegistry::getPassRegistry());
@@ -201,4 +227,5 @@
INITIALIZE_PASS_BEGIN(DPass, "dpass", "dpass", false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
INITIALIZE_PASS_END(DPass, "dpass", "dpass", false, false)