From bdccb0097061e05b506592c25b3b5e9e0692c950 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 22 Sep 2002 18:41:25 +0000
Subject: [PATCH] Don't insert a PHI node to merge "returns" from an inlined
 function if there is only a single return from the function!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3878 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/InlineSimple.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/Transforms/IPO/InlineSimple.cpp b/lib/Transforms/IPO/InlineSimple.cpp
index d88a923e225..41f849a7988 100644
--- a/lib/Transforms/IPO/InlineSimple.cpp
+++ b/lib/Transforms/IPO/InlineSimple.cpp
@@ -190,7 +190,18 @@ bool InlineFunction(CallInst *CI) {
       RemapInstruction(II, ValueMap);
   }
 
-  if (PHI) RemapInstruction(PHI, ValueMap);  // Fix the PHI node also...
+  if (PHI) {
+    RemapInstruction(PHI, ValueMap);  // Fix the PHI node also...
+
+    // Check to see if the PHI node only has one argument.  This is a common
+    // case resulting from there only being a single return instruction in the
+    // function call.  Because this is so common, eliminate the PHI node.
+    //
+    if (PHI->getNumIncomingValues() == 1) {
+      PHI->replaceAllUsesWith(PHI->getIncomingValue(0));
+      PHI->getParent()->getInstList().erase(PHI);
+    }
+  }
 
   // Change the branch that used to go to NewBB to branch to the first basic 
   // block of the inlined function.