The pass everyone has been waiting for!
Reg2Mem
for fun you can opt -reg2mem -mem2reg
llvm-svn: 24267
diff --git a/llvm/lib/Transforms/Scalar/Reg2Mem.cpp b/llvm/lib/Transforms/Scalar/Reg2Mem.cpp
new file mode 100644
index 0000000..be60b5a
--- /dev/null
+++ b/llvm/lib/Transforms/Scalar/Reg2Mem.cpp
@@ -0,0 +1,79 @@
+//===- Reg2Mem.cpp - Convert registers to allocas -------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file demotes all registers to memory references. It is intented to be
+// the inverse of PromoteMemoryToRegister. By converting to loads, the only
+// values live accross basic blocks are allocas and loads before phi nodes.
+// It is intended that this should make CFG hacking much easier.
+// To make later hacking easier, the entry block is split into two, such that
+// all introduced allocas and nothing else are in the entry block.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Pass.h"
+#include "llvm/Function.h"
+#include "llvm/Module.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/Instructions.h"
+#include "llvm/ADT/Statistic.h"
+
+#include <list>
+
+using namespace llvm;
+
+namespace {
+ Statistic<> NumDemoted("reg2mem", "Number of registers demoted");
+
+ struct RegToMem : public FunctionPass {
+
+ bool valueEscapes(Instruction* i) {
+ BasicBlock* bb = i->getParent();
+ for(Value::use_iterator ii = i->use_begin(), ie = i->use_end();
+ ii != ie; ++ii)
+ if (cast<Instruction>(*ii)->getParent() != bb)
+ return true;
+ return false;
+ }
+
+ virtual bool runOnFunction(Function &F) {
+ if (!F.isExternal()) {
+ //give us a clean block
+ BasicBlock& bbhead = F.getEntryBlock();
+ bbhead.splitBasicBlock(bbhead.begin());
+
+ //find the instructions
+ std::list<Instruction*> worklist;
+ for (Function::iterator ibb = F.begin(), ibe = F.end();
+ ibb != ibe; ++ibb)
+ for (BasicBlock::iterator iib = ibb->begin(), iie = ibb->end();
+ iib != iie; ++iib) {
+ if(valueEscapes(iib))
+ worklist.push_front(&*iib);
+ }
+ //demote escaped instructions
+ NumDemoted += worklist.size();
+ for (std::list<Instruction*>::iterator ilb = worklist.begin(),
+ ile = worklist.end(); ilb != ile; ++ilb)
+ DemoteRegToStack(**ilb, false);
+ return true;
+ }
+ return false;
+ }
+ };
+
+ RegisterOpt<RegToMem> X("reg2mem", "Demote all values to stack slots");
+}
+
+// createDemoteRegisterToMemory - Provide an entry point to create this pass.
+//
+FunctionPass *llvm::createDemoteRegisterToMemoryPass() {
+ return new RegToMem();
+}