From dfaceb49fca5ea37ded300dfe0867aa4b891f98b Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 20 Jun 2008 16:39:44 +0000
Subject: [PATCH] Fix the conditions under which SCCP should examine
 insertvalue instructions. Thanks to Matthijs Kooijman for pointing this out!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52542 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/SCCP.cpp | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index dc6d497bd00..3ca03b3c1d9 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -750,7 +750,7 @@ void SCCPSolver::visitInsertValueInst(InsertValueInst &IVI) {
   Value *Val = IVI.getOperand(1);
 
   // If the operand to the getresult is an undef, the result is undef.
-  if (isa<UndefValue>(Aggr))
+  if (isa<UndefValue>(Aggr) && isa<UndefValue>(Val))
     return;
 
   // Currently only handle single-index insertvalues.
@@ -758,6 +758,23 @@ void SCCPSolver::visitInsertValueInst(InsertValueInst &IVI) {
     markOverdefined(&IVI);
     return;
   }
+
+  // Currently only handle insertvalue instructions that are in a single-use
+  // chain that builds up a return value.
+  for (const InsertValueInst *TmpIVI = &IVI; ; ) {
+    if (!TmpIVI->hasOneUse()) {
+      markOverdefined(&IVI);
+      return;
+    }
+    const Value *V = *TmpIVI->use_begin();
+    if (isa<ReturnInst>(V))
+      break;
+    TmpIVI = dyn_cast<InsertValueInst>(V);
+    if (!TmpIVI) {
+      markOverdefined(&IVI);
+      return;
+    }
+  }
   
   // See if we are tracking the result of the callee.
   Function *F = IVI.getParent()->getParent();