[llvm-commits] [llvm] r56001 - in /llvm/trunk: lib/Transforms/IPO/GlobalOpt.cpp test/Transforms/GlobalOpt/alias-resolve.ll

[Anton Korobeynikov]

Author: asl
Date: Tue Sep  9 14:04:59 2008
New Revision: 56001

URL: http://llvm.org/viewvc/llvm-project?rev=56001&view=rev
Log:
Resolve aliases, when possible

Added:
    llvm/trunk/test/Transforms/GlobalOpt/alias-resolve.ll
Modified:
    llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp

Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=56001&r1=56000&r2=56001&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Tue Sep  9 14:04:59 2008
@@ -65,6 +65,7 @@
     GlobalVariable *FindGlobalCtors(Module &M);
     bool OptimizeFunctions(Module &M);
     bool OptimizeGlobalVars(Module &M);
+    bool ResolveAliases(Module &M);
     bool OptimizeGlobalCtorsList(GlobalVariable *&GCL);
     bool ProcessInternalGlobal(GlobalVariable *GV,Module::global_iterator &GVI);
   };
@@ -2214,6 +2215,23 @@
   return true;
 }
 
+bool GlobalOpt::ResolveAliases(Module &M) {
+  bool Changed = false;
+
+  for (Module::alias_iterator I = M.alias_begin(),
+         E = M.alias_end(); I != E; ++I) {
+    if (I->use_empty())
+      continue;
+
+    if (const GlobalValue *GV = I->resolveAliasedGlobal(/*traverseWeak*/ false))
+      if (GV != I) {
+        I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
+        Changed = true;
+      }
+  }
+
+  return Changed;
+}
 
 bool GlobalOpt::runOnModule(Module &M) {
   bool Changed = false;
@@ -2235,6 +2253,10 @@
     // Optimize non-address-taken globals.
     LocalChange |= OptimizeGlobalVars(M);
     Changed |= LocalChange;
+
+    // Resolve aliases, when possible.
+    LocalChange |= ResolveAliases(M);
+    Changed |= LocalChange;
   }
   
   // TODO: Move all global ctors functions to the end of the module for code

Added: llvm/trunk/test/Transforms/GlobalOpt/alias-resolve.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/alias-resolve.ll?rev=56001&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/alias-resolve.ll (added)
+++ llvm/trunk/test/Transforms/GlobalOpt/alias-resolve.ll Tue Sep  9 14:04:59 2008
@@ -0,0 +1,19 @@
+; RUN: llvm-as < %s | opt -globalopt | llvm-dis > %t
+; RUN: cat %t | grep foo1 | count 1
+; RUN: cat %t | grep foo2 | count 4
+; RUN: cat %t | grep bar1 | count 1
+; RUN: cat %t | grep bar2 | count 4
+
+ at foo1 = alias void ()* @foo2
+ at foo2 = alias weak void()* @bar1
+ at bar1  = alias void ()* @bar2
+
+declare void @bar2()
+
+define void @baz() {
+entry:
+        call void @foo1()
+        call void @foo2()
+        call void @bar1()
+        ret void
+}