From 5f8e79e6d22cff558fde9f3d40844a9eceaf79ac Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Thu, 2 Jan 2014 21:12:11 +0000
Subject: [PATCH] indvars: cleanup the IV visitor. It does more than gather
 sext/zext info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198353 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/IndVarSimplify.cpp | 58 ++++++++++++++----------
 1 file changed, 33 insertions(+), 25 deletions(-)

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index c992f8c12a6..6e141bd2d6a 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -637,30 +637,13 @@ namespace {
 
     WideIVInfo() : NarrowIV(0), WidestNativeType(0), IsSigned(false) {}
   };
-
-  class WideIVVisitor : public IVVisitor {
-    ScalarEvolution *SE;
-    const DataLayout *TD;
-
-  public:
-    WideIVInfo WI;
-
-    WideIVVisitor(PHINode *NarrowIV, ScalarEvolution *SCEV,
-                  const DataLayout *TData, const DominatorTree *DTree):
-      SE(SCEV), TD(TData) {
-      DT = DTree;
-      WI.NarrowIV = NarrowIV;
-    }
-
-    // Implement the interface used by simplifyUsersOfIV.
-    virtual void visitCast(CastInst *Cast);
-  };
 }
 
 /// visitCast - Update information about the induction variable that is
 /// extended by this sign or zero extend operation. This is used to determine
 /// the final width of the IV before actually widening it.
-void WideIVVisitor::visitCast(CastInst *Cast) {
+static void visitIVCast(CastInst *Cast, WideIVInfo &WI, ScalarEvolution *SE,
+                        const DataLayout *TD) {
   bool IsSigned = Cast->getOpcode() == Instruction::SExt;
   if (!IsSigned && Cast->getOpcode() != Instruction::ZExt)
     return;
@@ -1092,10 +1075,37 @@ PHINode *WidenIV::CreateWideIV(SCEVExpander &Rewriter) {
   return WidePhi;
 }
 
+//===----------------------------------------------------------------------===//
+//  Live IV Reduction - Minimize IVs live across the loop.
+//===----------------------------------------------------------------------===//
+
+
 //===----------------------------------------------------------------------===//
 //  Simplification of IV users based on SCEV evaluation.
 //===----------------------------------------------------------------------===//
 
+namespace {
+  class IndVarSimplifyVisitor : public IVVisitor {
+    ScalarEvolution *SE;
+    const DataLayout *TD;
+    PHINode *IVPhi;
+
+  public:
+    WideIVInfo WI;
+
+    IndVarSimplifyVisitor(PHINode *IV, ScalarEvolution *SCEV,
+                          const DataLayout *TData, const DominatorTree *DTree):
+      SE(SCEV), TD(TData), IVPhi(IV) {
+      DT = DTree;
+      WI.NarrowIV = IVPhi;
+      if (ReduceLiveIVs)
+        setSplitOverflowIntrinsics();
+    }
+
+    // Implement the interface used by simplifyUsersOfIV.
+    virtual void visitCast(CastInst *Cast) { visitIVCast(Cast, WI, SE, TD); }
+  };
+}
 
 /// SimplifyAndExtend - Iteratively perform simplification on a worklist of IV
 /// users. Each successive simplification may push more users which may
@@ -1127,14 +1137,12 @@ void IndVarSimplify::SimplifyAndExtend(Loop *L,
       PHINode *CurrIV = LoopPhis.pop_back_val();
 
       // Information about sign/zero extensions of CurrIV.
-      WideIVVisitor WIV(CurrIV, SE, TD, DT);
-      if (ReduceLiveIVs)
-        WIV.setSplitOverflowIntrinsics();
+      IndVarSimplifyVisitor Visitor(CurrIV, SE, TD, DT);
 
-      Changed |= simplifyUsersOfIV(CurrIV, SE, &LPM, DeadInsts, &WIV);
+      Changed |= simplifyUsersOfIV(CurrIV, SE, &LPM, DeadInsts, &Visitor);
 
-      if (WIV.WI.WidestNativeType) {
-        WideIVs.push_back(WIV.WI);
+      if (Visitor.WI.WidestNativeType) {
+        WideIVs.push_back(Visitor.WI);
       }
     } while(!LoopPhis.empty());
 
-- 
2.34.1