don't eliminate address-taken blocks here.

llvm-svn: 98550
This commit is contained in:
Chris Lattner 2010-03-15 16:37:42 +00:00
parent c73a361ac5
commit 51a6eb7d12
1 changed files with 15 additions and 3 deletions

View File

@ -58,13 +58,25 @@ FunctionPass *llvm::createUnreachableBlockEliminationPass() {
return new UnreachableBlockElim();
}
static void MarkReachableFrom(BasicBlock *BB,
SmallPtrSet<BasicBlock*, 8> &Reachable) {
for (df_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 8> > I =
df_ext_begin(BB, Reachable), E = df_ext_end(BB, Reachable); I != E; ++I)
; // Mark all reachable blocks.
}
bool UnreachableBlockElim::runOnFunction(Function &F) {
SmallPtrSet<BasicBlock*, 8> Reachable;
// Mark all reachable blocks.
for (df_ext_iterator<Function*, SmallPtrSet<BasicBlock*, 8> > I =
df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable); I != E; ++I)
/* Mark all reachable blocks */;
MarkReachableFrom(&F.getEntryBlock(), Reachable);
// Mark any address-taken blocks. We don't want codegen to delete these
// because the address may already be referenced by another function and the
// label may be referenced.
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
if (I->hasAddressTaken() && !Reachable.count(I))
MarkReachableFrom(I, Reachable);
// Loop over all dead blocks, remembering them and deleting all instructions
// in them.