From: Chris Lattner <sabre@nondot.org>
Date: Tue, 14 Feb 2006 23:06:02 +0000 (+0000)
Subject: Canonicalize inner loops before outer loops.  Inner loop canonicalization
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0ab9f966de73911930b47ce09f2a691bc687ed32;p=oota-llvm.git

Canonicalize inner loops before outer loops.  Inner loop canonicalization
can provide work for the outer loop to canonicalize.

This fixes a case that breaks unswitching.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26189 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index a41692b4c26..3188f123b7f 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -115,7 +115,11 @@ bool LoopSimplify::runOnFunction(Function &F) {
 ///
 bool LoopSimplify::ProcessLoop(Loop *L) {
   bool Changed = false;
-
+  // Canonicalize inner loops before outer loops.  Inner loop canonicalization
+  // can provide work for the outer loop to canonicalize.
+  for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
+    Changed |= ProcessLoop(*I);
+  
   // Check to see that no blocks (other than the header) in the loop have
   // predecessors that are not in the loop.  This is not valid for natural
   // loops, but can occur if the blocks are unreachable.  Since they are
@@ -205,9 +209,6 @@ bool LoopSimplify::ProcessLoop(Loop *L) {
         PN->eraseFromParent();
       }
 
-  for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
-    Changed |= ProcessLoop(*I);
-
   return Changed;
 }