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 {
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());
++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
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;
}
--- /dev/null
+; RUN: llvm-as < %s | opt -prune-eh | llvm-dis | not grep unwind_to
+
+define i8 @test7(i1 %b) {
+entry: unwind_to %cleanup
+ br i1 %b, label %cond_true, label %cond_false
+cond_true: unwind_to %cleanup
+ br label %cleanup
+cond_false: unwind_to %cleanup
+ br label %cleanup
+cleanup:
+ %x = phi i8 [0, %entry], [1, %cond_true], [1, %cond_true],
+ [2, %cond_false], [2, %cond_false]
+ ret i8 %x
+}
+