X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FPasses.cpp;h=c62227535fc99c0cd039cf7be2cac6a254eca879;hb=b34d837397053da8e9bff90dd714e24f2a3b98b3;hp=6742146a3833aa5a63c469d661e3879230114e99;hpb=4ee451de366474b9c228b4e5fa573795a715216d;p=oota-llvm.git

diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index 6742146a383..c62227535fc 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -24,19 +24,22 @@ using namespace llvm;
 //===---------------------------------------------------------------------===//
 MachinePassRegistry RegisterRegAlloc::Registry;
 
+static FunctionPass *createDefaultRegisterAllocator() { return 0; }
+static RegisterRegAlloc
+defaultRegAlloc("default",
+                "pick register allocator based on -O option",
+                createDefaultRegisterAllocator);
 
 //===---------------------------------------------------------------------===//
 ///
 /// RegAlloc command line options.
 ///
 //===---------------------------------------------------------------------===//
-namespace {
-  cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
-          RegisterPassParser<RegisterRegAlloc> >
-  RegAlloc("regalloc",
-           cl::init(&createLinearScanRegisterAllocator),
-           cl::desc("Register allocator to use: (default = linearscan)")); 
-}
+static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
+               RegisterPassParser<RegisterRegAlloc> >
+RegAlloc("regalloc",
+         cl::init(&createDefaultRegisterAllocator),
+         cl::desc("Register allocator to use"));
 
 
 //===---------------------------------------------------------------------===//
@@ -44,13 +47,27 @@ namespace {
 /// createRegisterAllocator - choose the appropriate register allocator.
 ///
 //===---------------------------------------------------------------------===//
-FunctionPass *llvm::createRegisterAllocator() {
+FunctionPass *llvm::createRegisterAllocator(CodeGenOpt::Level OptLevel) {
   RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
-  
+
   if (!Ctor) {
     Ctor = RegAlloc;
     RegisterRegAlloc::setDefault(RegAlloc);
   }
-  
-  return Ctor();
+
+  // This forces linking of the greedy register allocator, so -regalloc=greedy
+  // works in clang.
+  if (Ctor == createGreedyRegisterAllocator)
+    return createGreedyRegisterAllocator();
+
+  if (Ctor != createDefaultRegisterAllocator)
+    return Ctor();
+
+  // When the 'default' allocator is requested, pick one based on OptLevel.
+  switch (OptLevel) {
+  case CodeGenOpt::None:
+    return createFastRegisterAllocator();
+  default:
+    return createLinearScanRegisterAllocator();
+  }
 }