Enable stack coloring by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52057 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index d3e8e4904fee2efc49a03614291728b2f5ee5dce..1c8ce0a44c44b91e997b6c9abda92bd97ca14d15 100644 (file)
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -38,10 +38,6 @@ static cl::opt<bool>
 EnableSinking("enable-sinking", cl::init(false), cl::Hidden,
               cl::desc("Perform sinking on machine code"));
 static cl::opt<bool>
-EnableStackColoring("stack-coloring",
-            cl::init(false), cl::Hidden,
-            cl::desc("Perform stack slot coloring"));
-static cl::opt<bool>
 EnableLICM("machine-licm",
            cl::init(false), cl::Hidden,
            cl::desc("Perform loop-invariant code motion on machine code"));
@@ -103,8 +99,7 @@ LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
   PM.add(createRegisterAllocator());
   
   // Perform stack slot coloring.
-  if (EnableStackColoring)
-    PM.add(createStackSlotColoringPass());
+  PM.add(createStackSlotColoringPass());
 
   if (PrintMachineCode)  // Print the register-allocated code
     PM.add(createMachineFunctionPrinterPass(cerr));
@@ -240,8 +235,7 @@ bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
   PM.add(createRegisterAllocator());
 
   // Perform stack slot coloring.
-  if (EnableStackColoring)
-    PM.add(createStackSlotColoringPass());
+  PM.add(createStackSlotColoringPass());
 
   if (PrintMachineCode)
     PM.add(createMachineFunctionPrinterPass(cerr));

diff --git a/lib/CodeGen/README.txt b/lib/CodeGen/README.txt
index a66fc9dcdccd555575118e3302bc7214adf8e6b9..d5ddd217962100d8b2c0c70e867dee3ae9282d64 100644 (file)
--- a/lib/CodeGen/README.txt
+++ b/lib/CodeGen/README.txt
@@ -197,3 +197,12 @@ It would be really nice to be able to write patterns in .td files for copies,
 which would eliminate a bunch of explicit predicates on them (e.g. no side 
 effects).  Once this is in place, it would be even better to have tblgen 
 synthesize the various copy insertion/inspection methods in TargetInstrInfo.
+
+//===---------------------------------------------------------------------===//
+
+Stack coloring improvments:
+
+1. Do proper LiveStackAnalysis on all stack objects including those which are
+   not spill slots.
+2. Reorder objects to fill in gaps between objects.
+   e.g. 4, 1, <gap>, 4, 1, 1, 1, <gap>, 4 => 4, 1, 1, 1, 1, 4, 4