InstCombine: Use isAllOnesValue() instead of explicit -1.

[oota-llvm.git] / lib / Transforms / IPO / GlobalDCE.cpp

diff --git a/lib/Transforms/IPO/GlobalDCE.cpp b/lib/Transforms/IPO/GlobalDCE.cpp
index 129cb7c46e0b1ad914ad101a416f3964d0168cac..201f320c43bd155eb6b2ad4e523c1c6767e538c5 100644 (file)
--- a/lib/Transforms/IPO/GlobalDCE.cpp
+++ b/lib/Transforms/IPO/GlobalDCE.cpp
@@ -17,11 +17,11 @@
 
 #define DEBUG_TYPE "globaldce"
 #include "llvm/Transforms/IPO.h"
-#include "llvm/Constants.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
 using namespace llvm;
 
 STATISTIC(NumAliases  , "Number of global aliases removed");
@@ -31,7 +31,9 @@ STATISTIC(NumVariables, "Number of global variables removed");
 namespace {
   struct GlobalDCE : public ModulePass {
     static char ID; // Pass identification, replacement for typeid
-    GlobalDCE() : ModulePass(&ID) {}
+    GlobalDCE() : ModulePass(ID) {
+      initializeGlobalDCEPass(*PassRegistry::getPassRegistry());
+    }
 
     // run - Do the GlobalDCE pass on the specified module, optionally updating
     // the specified callgraph to reflect the changes.
@@ -40,6 +42,7 @@ namespace {
 
   private:
     SmallPtrSet<GlobalValue*, 32> AliveGlobals;
+    SmallPtrSet<Constant *, 8> SeenConstants;
 
     /// GlobalIsNeeded - mark the specific global value as needed, and
     /// recursively mark anything that it uses as also needed.
@@ -52,7 +55,7 @@ namespace {
 
 char GlobalDCE::ID = 0;
 INITIALIZE_PASS(GlobalDCE, "globaldce",
-                "Dead Global Elimination", false, false);
+                "Dead Global Elimination", false, false)
 
 ModulePass *llvm::createGlobalDCEPass() { return new GlobalDCE(); }
 
@@ -63,7 +66,7 @@ bool GlobalDCE::runOnModule(Module &M) {
   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
     Changed |= RemoveUnusedGlobalValue(*I);
     // Functions with external linkage are needed if they have a body
-    if (!I->hasLocalLinkage() && !I->hasLinkOnceLinkage() &&
+    if (!I->isDiscardableIfUnused() &&
         !I->isDeclaration() && !I->hasAvailableExternallyLinkage())
       GlobalIsNeeded(I);
   }
@@ -73,7 +76,7 @@ bool GlobalDCE::runOnModule(Module &M) {
     Changed |= RemoveUnusedGlobalValue(*I);
     // Externally visible & appending globals are needed, if they have an
     // initializer.
-    if (!I->hasLocalLinkage() && !I->hasLinkOnceLinkage() &&
+    if (!I->isDiscardableIfUnused() &&
         !I->isDeclaration() && !I->hasAvailableExternallyLinkage())
       GlobalIsNeeded(I);
   }
@@ -82,7 +85,7 @@ bool GlobalDCE::runOnModule(Module &M) {
        I != E; ++I) {
     Changed |= RemoveUnusedGlobalValue(*I);
     // Externally visible aliases are needed.
-    if (!I->hasLocalLinkage() && !I->hasLinkOnceLinkage())
+    if (!I->isDiscardableIfUnused())
       GlobalIsNeeded(I);
   }
 
@@ -149,6 +152,7 @@ bool GlobalDCE::runOnModule(Module &M) {
 
   // Make sure that all memory is released
   AliveGlobals.clear();
+  SeenConstants.clear();
 
   return Changed;
 }
@@ -188,12 +192,15 @@ void GlobalDCE::GlobalIsNeeded(GlobalValue *G) {
 void GlobalDCE::MarkUsedGlobalsAsNeeded(Constant *C) {
   if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
     return GlobalIsNeeded(GV);
-  
+
   // Loop over all of the operands of the constant, adding any globals they
   // use to the list of needed globals.
-  for (User::op_iterator I = C->op_begin(), E = C->op_end(); I != E; ++I)
-    if (Constant *OpC = dyn_cast<Constant>(*I))
-      MarkUsedGlobalsAsNeeded(OpC);
+  for (User::op_iterator I = C->op_begin(), E = C->op_end(); I != E; ++I) {
+    // If we've already processed this constant there's no need to do it again.
+    Constant *Op = dyn_cast<Constant>(*I);
+    if (Op && SeenConstants.insert(Op))
+      MarkUsedGlobalsAsNeeded(Op);
+  }
 }
 
 // RemoveUnusedGlobalValue - Loop over all of the uses of the specified