Introduce ImmutableCallSite, useful for contexts where no mutation

[oota-llvm.git] / lib / Transforms / Scalar / SCCP.cpp

diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 5a0f62083efa3431aadfbf6e9e49c28694f0e518..546b7b6cc292081fd3436474a46d19c7e2d5c13e 100644 (file)
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -1705,28 +1705,31 @@ ModulePass *llvm::createIPSCCPPass() {
 }
 
 
-static bool AddressIsTaken(GlobalValue *GV) {
+static bool AddressIsTaken(const GlobalValue *GV) {
   // Delete any dead constantexpr klingons.
   GV->removeDeadConstantUsers();
 
-  for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end();
-       UI != E; ++UI)
-    if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) {
+  for (Value::const_use_iterator UI = GV->use_begin(), E = GV->use_end();
+       UI != E; ++UI) {
+    const User *U = *UI;
+    if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
       if (SI->getOperand(0) == GV || SI->isVolatile())
         return true;  // Storing addr of GV.
-    } else if (isa<InvokeInst>(*UI) || isa<CallInst>(*UI)) {
+    } else if (isa<InvokeInst>(U) || isa<CallInst>(U)) {
       // Make sure we are calling the function, not passing the address.
-      if (UI.getOperandNo() != 0)
+      ImmutableCallSite CS(cast<Instruction>(U));
+      if (!CS.isCallee(UI))
         return true;
-    } else if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) {
+    } else if (const LoadInst *LI = dyn_cast<LoadInst>(U)) {
       if (LI->isVolatile())
         return true;
-    } else if (isa<BlockAddress>(*UI)) {
+    } else if (isa<BlockAddress>(U)) {
       // blockaddress doesn't take the address of the function, it takes addr
       // of label.
     } else {
       return true;
     }
+  }
   return false;
 }
 
@@ -1921,9 +1924,9 @@ bool IPSCCP::runOnModule(Module &M) {
   //
   // Do this in two stages: first identify the functions we should process, then
   // actually zap their returns.  This is important because we can only do this
-  // the address of the function isn't taken.  In cases where a return is the
+  // if the address of the function isn't taken.  In cases where a return is the
   // last use of a function, the order of processing functions would affect
-  // whether we other functions are optimizable.
+  // whether other functions are optimizable.
   SmallVector<ReturnInst*, 8> ReturnsToZap;
   
   // TODO: Process multiple value ret instructions also.