Prune the unwind_to labels on BBs that don't need them. Another step in the
removal of invoke, PR1269.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48084 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/PruneEH.cpp b/lib/Transforms/IPO/PruneEH.cpp
index 4e621dc..fa8b95a 100644
--- a/lib/Transforms/IPO/PruneEH.cpp
+++ b/lib/Transforms/IPO/PruneEH.cpp
@@ -32,6 +32,7 @@
STATISTIC(NumRemoved, "Number of invokes removed");
STATISTIC(NumUnreach, "Number of noreturn calls optimized");
+STATISTIC(NumBBUnwind, "Number of unwind_to removed from blocks");
namespace {
struct VISIBILITY_HIDDEN PruneEH : public CallGraphSCCPass {
@@ -153,6 +154,8 @@
bool PruneEH::SimplifyFunction(Function *F) {
bool MadeChange = false;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+ bool couldUnwind = false;
+
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
if (II->doesNotThrow()) {
SmallVector<Value*, 8> Args(II->op_begin()+3, II->op_end());
@@ -182,10 +185,11 @@
++NumRemoved;
MadeChange = true;
- }
+ } else
+ couldUnwind = true;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
- if (CallInst *CI = dyn_cast<CallInst>(I++))
+ if (CallInst *CI = dyn_cast<CallInst>(I++)) {
if (CI->doesNotReturn() && !isa<UnreachableInst>(I)) {
// This call calls a function that cannot return. Insert an
// unreachable instruction after it and simplify the code. Do this
@@ -201,8 +205,17 @@
MadeChange = true;
++NumUnreach;
break;
- }
+ } else if (!CI->doesNotThrow())
+ couldUnwind = true;
+ }
+ // Strip 'unwindTo' off of BBs that have no calls/invokes without nounwind.
+ if (!couldUnwind && BB->getUnwindDest()) {
+ MadeChange = true;
+ ++NumBBUnwind;
+ BB->getUnwindDest()->removePredecessor(BB, false, true);
+ BB->setUnwindDest(NULL);
+ }
}
return MadeChange;
}