From d920b5b7703fedaf4f4bf7f13df94aed33ff6c38 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Wed, 10 Nov 2004 19:43:59 +0000
Subject: [PATCH] Make IP Constant prop more aggressive about handling self
 recursive calls. This implements IPConstantProp/recursion.ll

llvm-svn: 17666
---
 lib/Transforms/IPO/IPConstantPropagation.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/Transforms/IPO/IPConstantPropagation.cpp b/lib/Transforms/IPO/IPConstantPropagation.cpp
index a1e09e6beff..479f8e73ccb 100644
--- a/lib/Transforms/IPO/IPConstantPropagation.cpp
+++ b/lib/Transforms/IPO/IPConstantPropagation.cpp
@@ -81,7 +81,9 @@ bool IPCP::processFunction(Function &F) {
       
       // Check out all of the potentially constant arguments
       CallSite::arg_iterator AI = CS.arg_begin();
-      for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI) {
+      Function::aiterator Arg = F.abegin();
+      for (unsigned i = 0, e = ArgumentConstants.size(); i != e;
+           ++i, ++AI, ++Arg) {
         if (*AI == &F) return false;  // Passes the function into itself
 
         if (!ArgumentConstants[i].second) {
@@ -94,7 +96,7 @@ bool IPCP::processFunction(Function &F) {
               ++NumNonconstant;
               if (NumNonconstant == ArgumentConstants.size()) return false;
             }
-          } else {
+          } else if (*AI != &*Arg) {    // Ignore recursive calls with same arg
             // This is not a constant argument.  Mark the argument as
             // non-constant.
             ArgumentConstants[i].second = true;