From 088b639e3a168686f16bb292e08b952d01a25b7d Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 3 Mar 2003 17:13:31 +0000
Subject: [PATCH] Don't apply type information to load instructions if it will
 cause collapsing

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5684 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/DataStructure/DataStructure.cpp | 11 ++++++-----
 lib/Analysis/DataStructure/Local.cpp         |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index 27247897e57..1aad8cf69ee 100644
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -152,7 +152,8 @@ bool DSNode::isNodeCompletelyFolded() const {
 ///
 /// This method returns true if the node is completely folded, otherwise false.
 ///
-bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
+bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
+                           bool FoldIfIncompatible) {
   // Check to make sure the Size member is up-to-date.  Size can be one of the
   // following:
   //  Size = 0, Ty = Void: Nothing is known about this node.
@@ -213,14 +214,14 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
     // It is illegal to grow this node if we have treated it as an array of
     // objects...
     if (isArray()) {
-      foldNodeCompletely();
+      if (FoldIfIncompatible) foldNodeCompletely();
       return true;
     }
 
     if (Offset) {  // We could handle this case, but we don't for now...
       DEBUG(std::cerr << "UNIMP: Trying to merge a growth type into "
                       << "offset != 0: Collapsing!\n");
-      foldNodeCompletely();
+      if (FoldIfIncompatible) foldNodeCompletely();
       return true;
     }
 
@@ -277,7 +278,7 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
       break;
     }
     default:
-      foldNodeCompletely();
+      if (FoldIfIncompatible) foldNodeCompletely();
       return true;
     }
   }
@@ -356,7 +357,7 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
                   << "\n due to:" << NewTy << " @ " << Offset << "!\n"
                   << "SubType: " << SubType << "\n\n");
 
-  foldNodeCompletely();
+  if (FoldIfIncompatible) foldNodeCompletely();
   return true;
 }
 
diff --git a/lib/Analysis/DataStructure/Local.cpp b/lib/Analysis/DataStructure/Local.cpp
index ffc80e73a6a..005580155d6 100644
--- a/lib/Analysis/DataStructure/Local.cpp
+++ b/lib/Analysis/DataStructure/Local.cpp
@@ -368,7 +368,7 @@ void GraphBuilder::visitLoadInst(LoadInst &LI) {
   Ptr.getNode()->NodeType |= DSNode::Read;
 
   // Ensure a typerecord exists...
-  Ptr.getNode()->mergeTypeInfo(LI.getType(), Ptr.getOffset());
+  Ptr.getNode()->mergeTypeInfo(LI.getType(), Ptr.getOffset(), false);
 
   if (isPointerType(LI.getType()))
     setDestTo(LI, getLink(Ptr));