From 535d97cc86326ccc24cbb0c03eb059d07d172912 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Sat, 2 Feb 2013 00:25:26 +0000
Subject: [PATCH] Revert accidental commit (ran svn commit from wrong
 directory).

llvm-svn: 174241
---
 .../IPO/DeadArgumentElimination.cpp           | 68 ++-----------------
 1 file changed, 7 insertions(+), 61 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
index 512f19df6232..49ef1e75f1cd 100644
--- a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -36,14 +36,12 @@
 #include "llvm/Support/CallSite.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Utils/Local.h"
 #include <map>
 #include <set>
 using namespace llvm;
 
-STATISTIC(NumArgumentsEliminated , "Number of unread args removed");
-STATISTIC(NumRetValsEliminated   , "Number of unused return values removed");
-STATISTIC(NumParametersEliminated, "Number of parameters replaced with undef");
+STATISTIC(NumArgumentsEliminated, "Number of unread args removed");
+STATISTIC(NumRetValsEliminated  , "Number of unused return values removed");
 STATISTIC(NumArgumentsReplacedWithUndef, 
           "Number of unread args replaced with undef");
 namespace {
@@ -163,7 +161,6 @@ namespace {
     void MarkLive(const Function &F);
     void PropagateLiveness(const RetOrArg &RA);
     bool RemoveDeadStuffFromFunction(Function *F);
-    bool RemoveDeadParamsFromCallersOf(Function *F);
     bool DeleteDeadVarargs(Function &Fn);
     bool RemoveDeadArgumentsFromCallers(Function &Fn);
   };
@@ -252,7 +249,8 @@ bool DAE::DeleteDeadVarargs(Function &Fn) {
   FunctionType *FTy = Fn.getFunctionType();
 
   std::vector<Type*> Params(FTy->param_begin(), FTy->param_end());
-  FunctionType *NFTy = FunctionType::get(FTy->getReturnType(), Params, false);
+  FunctionType *NFTy = FunctionType::get(FTy->getReturnType(),
+                                                Params, false);
   unsigned NumArgs = Params.size();
 
   // Create the new function body and insert it into the module...
@@ -507,9 +505,7 @@ DAE::Liveness DAE::SurveyUses(const Value *V, UseVector &MaybeLiveUses) {
 // map.
 //
 // We consider arguments of non-internal functions to be intrinsically alive as
-// well as arguments to functions which have their "address taken". Externally
-// visible functions are assumed to only have their return values intrinsically
-// alive, permitting removal of parameters to unused arguments in callers.
+// well as arguments to functions which have their "address taken".
 //
 void DAE::SurveyFunction(const Function &F) {
   unsigned RetCount = NumRetVals(&F);
@@ -532,14 +528,7 @@ void DAE::SurveyFunction(const Function &F) {
         return;
       }
 
-  if (F.hasExternalLinkage() && !F.isDeclaration()) {
-    DEBUG(dbgs() << "DAE - Intrinsically live return from " << F.getName()
-                 << "\n");
-    // Mark the return values alive.
-    for (unsigned i = 0, e = NumRetVals(&F); i != e; ++i)
-      MarkLive(CreateRet(&F, i));
-  } else if (!F.hasLocalLinkage() &&
-             (!ShouldHackArguments() || F.isIntrinsic())) {
+  if (!F.hasLocalLinkage() && (!ShouldHackArguments() || F.isIntrinsic())) {
     MarkLive(F);
     return;
   }
@@ -1043,46 +1032,6 @@ bool DAE::RemoveDeadStuffFromFunction(Function *F) {
   return true;
 }
 
-// RemoveDeadParamsFromCallersOf - Replace any parameters that are never used
-// by the callee with undef.
-//
-bool DAE::RemoveDeadParamsFromCallersOf(Function *F) {
-  // Don't modify fully live functions
-  if (LiveFunctions.count(F))
-    return false;
-
-  // Make a list of the dead arguments.
-  SmallVector<int, 10> ArgDead;
-  unsigned i = 0;
-  for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end();
-       I != E; ++I, ++i) {
-    RetOrArg Arg = CreateArg(F, i);
-    if (!LiveValues.count(Arg))
-      ArgDead.push_back(i);
-  }
-  if (ArgDead.empty())
-    return false;
-
-  bool MadeChange = false;
-  for (Function::use_iterator I = F->use_begin(), E = F->use_end();
-       I != E; ++I) {
-    CallSite CS = CallSite(*I);
-    if (CS.getInstruction() && CS.isCallee(I)) {
-      for (unsigned i = 0, e = ArgDead.size(); i != e; ++i) {
-        Value *A = CS.getArgument(ArgDead[i]);
-        if (!isa<UndefValue>(A)) {
-          ++NumParametersEliminated;
-          MadeChange = true;
-          CS.setArgument(ArgDead[i], UndefValue::get(A->getType()));
-          RecursivelyDeleteTriviallyDeadInstructions(A);
-        }
-      }
-    }
-  }
-
-  return MadeChange;
-}
-
 bool DAE::runOnModule(Module &M) {
   bool Changed = false;
 
@@ -1114,10 +1063,7 @@ bool DAE::runOnModule(Module &M) {
     // Increment now, because the function will probably get removed (ie.
     // replaced by a new one).
     Function *F = I++;
-    if (F->hasExternalLinkage() && !F->isDeclaration())
-      Changed |= RemoveDeadParamsFromCallersOf(F);
-    else
-      Changed |= RemoveDeadStuffFromFunction(F);
+    Changed |= RemoveDeadStuffFromFunction(F);
   }
 
   // Finally, look for any unused parameters in functions with non-local