From 97f3f7e819ecc0c94190464987b4a685acf607e3 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 13 Oct 2003 16:36:06 +0000
Subject: [PATCH] Make use of "external" depth-first iterators to avoid
 revisiting nodes multiple times.  This reduces the time to construct
 post-dominance sets a LOT. For example, optimizing perlbmk goes from taking
 12.9894s to 1.4074s.

llvm-svn: 9091
---
 lib/Analysis/PostDominators.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index f97fda854e5..2ff5fd331ab 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -51,12 +51,12 @@ bool PostDominatorSet::runOnFunction(Function &F) {
   do {
     Changed = false;
 
-    std::set<const BasicBlock*> Visited;
+    std::set<BasicBlock*> Visited;
     DomSetType WorkingSet;
 
     for (unsigned i = 0, e = Roots.size(); i != e; ++i)
-      for (idf_iterator<BasicBlock*> It = idf_begin(Roots[i]),
-             E = idf_end(Roots[i]); It != E; ++It) {
+      for (idf_ext_iterator<BasicBlock*> It = idf_ext_begin(Roots[i], Visited),
+             E = idf_ext_end(Roots[i], Visited); It != E; ++It) {
         BasicBlock *BB = *It;
         succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
         if (SI != SE) {                // Is there SOME successor?