CodeGen: Refactor regallocator command line and target selection

This will allow targets more flexibility to replace the
register allocator core passes. In a future commit,
AMDGPU will run the core register assignment passes
twice, and will also want to disallow using the
standard -regalloc option.

llvm-svn: 356506

1 files changed, 34 insertions, 27 deletions

diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index 76275da38fe..8ddde4b8f99 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -897,13 +897,9 @@ void TargetPassConfig::addMachinePasses() {
   // Run register allocation and passes that are tightly coupled with it,
   // including phi elimination and scheduling.
   if (getOptimizeRegAlloc())
-    addOptimizedRegAlloc(createRegAllocPass(true));
-  else {
-    if (RegAlloc != &useDefaultRegisterAllocator &&
-        RegAlloc != &createFastRegisterAllocator)
-      report_fatal_error("Must use fast (default) register allocator for unoptimized regalloc.");
-    addFastRegAlloc(createRegAllocPass(false));
-  }
+    addOptimizedRegAlloc();
+  else
+    addFastRegAlloc();
 
   // Run post-ra passes.
   addPostRegAlloc();
@@ -1093,6 +1089,33 @@ FunctionPass *TargetPassConfig::createRegAllocPass(bool Optimized) {
   return createTargetRegisterAllocator(Optimized);
 }
 
+bool TargetPassConfig::addRegAssignmentFast() {
+  if (RegAlloc != &useDefaultRegisterAllocator &&
+      RegAlloc != &createFastRegisterAllocator)
+    report_fatal_error("Must use fast (default) register allocator for unoptimized regalloc.");
+
+  addPass(createRegAllocPass(false));
+  return true;
+}
+
+bool TargetPassConfig::addRegAssignmentOptimized() {
+  // Add the selected register allocation pass.
+  addPass(createRegAllocPass(true));
+
+  // Allow targets to change the register assignments before rewriting.
+  addPreRewrite();
+
+  // Finally rewrite virtual registers.
+  addPass(&VirtRegRewriterID);
+  // Perform stack slot coloring and post-ra machine LICM.
+  //
+  // FIXME: Re-enable coloring with register when it's capable of adding
+  // kill markers.
+  addPass(&StackSlotColoringID);
+
+  return true;
+}
+
 /// Return true if the default global register allocator is in use and
 /// has not be overriden on the command line with '-regalloc=...'
 bool TargetPassConfig::usingDefaultRegAlloc() const {
@@ -1101,18 +1124,17 @@ bool TargetPassConfig::usingDefaultRegAlloc() const {
 
 /// Add the minimum set of target-independent passes that are required for
 /// register allocation. No coalescing or scheduling.
-void TargetPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
+void TargetPassConfig::addFastRegAlloc() {
   addPass(&PHIEliminationID, false);
   addPass(&TwoAddressInstructionPassID, false);
 
-  if (RegAllocPass)
-    addPass(RegAllocPass);
+  addRegAssignmentFast();
 }
 
 /// Add standard target-independent passes that are tightly coupled with
 /// optimized register allocation, including coalescing, machine instruction
 /// scheduling, and register allocation itself.
-void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
+void TargetPassConfig::addOptimizedRegAlloc() {
   addPass(&DetectDeadLanesID, false);
 
   addPass(&ProcessImplicitDefsID, false);
@@ -1144,22 +1166,7 @@ void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
   // PreRA instruction scheduling.
   addPass(&MachineSchedulerID);
 
-  if (RegAllocPass) {
-    // Add the selected register allocation pass.
-    addPass(RegAllocPass);
-
-    // Allow targets to change the register assignments before rewriting.
-    addPreRewrite();
-
-    // Finally rewrite virtual registers.
-    addPass(&VirtRegRewriterID);
-
-    // Perform stack slot coloring and post-ra machine LICM.
-    //
-    // FIXME: Re-enable coloring with register when it's capable of adding
-    // kill markers.
-    addPass(&StackSlotColoringID);
-
+  if (addRegAssignmentOptimized()) {
     // Copy propagate to forward register uses and try to eliminate COPYs that
     // were not coalesced.
     addPass(&MachineCopyPropagationID);