Remove always-true comparison, NFC.

Summary:
Looking at r241279, I noticed that UpgradedIntrinsics only gets written
to in the following code:

    if (UpgradeIntrinsicFunction(&F, NewFn))
      UpgradedIntrinsics[&F] = NewFn;

Looking through UpgradeIntrinsicFunction, we always return false OR
NewFn will be set to a different function from our source.

This patch pulls the F != NewFn into UpgradeIntrinsicFunction as an
assert, and removes the check from callers of UpgradeIntrinsicFunction.

Reviewers: rafael, chandlerc

Subscribers: llvm-commits-list

Differential Revision: http://reviews.llvm.org/D10915

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241369 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -4458,14 +4458,11 @@ std::error_code BitcodeReader::materialize(GlobalValue *GV) {
 
   // Upgrade any old intrinsic calls in the function.
   for (auto &I : UpgradedIntrinsics) {
-    if (I.first != I.second) {
-      for (auto UI = I.first->user_begin(), UE = I.first->user_end();
-           UI != UE;) {
-        User *U = *UI;
-        ++UI;
-        if (CallInst *CI = dyn_cast<CallInst>(U))
-          UpgradeIntrinsicCall(CI, I.second);
-      }
+    for (auto UI = I.first->user_begin(), UE = I.first->user_end(); UI != UE;) {
+      User *U = *UI;
+      ++UI;
+      if (CallInst *CI = dyn_cast<CallInst>(U))
+        UpgradeIntrinsicCall(CI, I.second);
     }
   }
 
@@ -4533,15 +4530,13 @@ std::error_code BitcodeReader::materializeModule(Module *M) {
   // module is materialized because there could always be another function body
   // with calls to the old function.
   for (auto &I : UpgradedIntrinsics) {
-    if (I.first != I.second) {
-      for (auto *U : I.first->users()) {
-        if (CallInst *CI = dyn_cast<CallInst>(U))
-          UpgradeIntrinsicCall(CI, I.second);
-      }
-      if (!I.first->use_empty())
-        I.first->replaceAllUsesWith(I.second);
-      I.first->eraseFromParent();
+    for (auto *U : I.first->users()) {
+      if (CallInst *CI = dyn_cast<CallInst>(U))
+        UpgradeIntrinsicCall(CI, I.second);
     }
+    if (!I.first->use_empty())
+      I.first->replaceAllUsesWith(I.second);
+    I.first->eraseFromParent();
   }
   UpgradedIntrinsics.clear();
 

lib/IR/AutoUpgrade.cpp

@@ -229,6 +229,7 @@ static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
 bool llvm::UpgradeIntrinsicFunction(Function *F, Function *&NewFn) {
   NewFn = nullptr;
   bool Upgraded = UpgradeIntrinsicFunction1(F, NewFn);
+  assert(F != NewFn && "Intrinsic function upgraded to the same function");
 
   // Upgrade intrinsic attributes.  This does not change the function.
   if (NewFn)
@@ -710,16 +711,14 @@ void llvm::UpgradeCallsToIntrinsic(Function* F) {
   // Upgrade the function and check if it is a totaly new function.
   Function *NewFn;
   if (UpgradeIntrinsicFunction(F, NewFn)) {
-    if (NewFn != F) {
-      // Replace all uses to the old function with the new one if necessary.
-      for (Value::user_iterator UI = F->user_begin(), UE = F->user_end();
-           UI != UE; ) {
-        if (CallInst *CI = dyn_cast<CallInst>(*UI++))
-          UpgradeIntrinsicCall(CI, NewFn);
-      }
-      // Remove old function, no longer used, from the module.
-      F->eraseFromParent();
+    // Replace all uses to the old function with the new one if necessary.
+    for (Value::user_iterator UI = F->user_begin(), UE = F->user_end();
+         UI != UE;) {
+      if (CallInst *CI = dyn_cast<CallInst>(*UI++))
+        UpgradeIntrinsicCall(CI, NewFn);
     }
+    // Remove old function, no longer used, from the module.
+    F->eraseFromParent();
   }
 }