Add an experimental -early-live-intervals option.

This option runs LiveIntervals before TwoAddressInstructionPass which
will eventually learn to exploit and update the analysis.

Eventually, LiveIntervals will run before PHIElimination, and we can get
rid of LiveVariables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161270 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h
index 0cddff8d9dacf9389d91200e796cb31655b1ad53..07b3b45873ae71469adc5f90c6acecdf4c5e2577 100644 (file)
--- a/include/llvm/CodeGen/Passes.h
+++ b/include/llvm/CodeGen/Passes.h
@@ -315,6 +315,10 @@ namespace llvm {
   ///  This pass is still in development
   extern char &StrongPHIEliminationID;
 
+  /// LiveIntervals - This analysis keeps track of the live ranges of virtual
+  /// and physical registers.
+  extern char &LiveIntervalsID;
+
   /// LiveStacks pass. An analysis keeping track of the liveness of stack slots.
   extern char &LiveStacksID;
 

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index b488e8f077e6d7fbc8dfa6b0d65d415d27c11f2f..d0f8ae1af30555a88fd21272bd3e0547237c2254 100644 (file)
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -45,6 +45,7 @@ NewLiveIntervals("new-live-intervals", cl::Hidden,
                  cl::desc("Use new algorithm forcomputing live intervals"));
 
 char LiveIntervals::ID = 0;
+char &llvm::LiveIntervalsID = LiveIntervals::ID;
 INITIALIZE_PASS_BEGIN(LiveIntervals, "liveintervals",
                 "Live Interval Analysis", false, false)
 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)

diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index 69d6d00091adb225b45be12d5f56e6c7e73fd558..cfa3eecf02ef14a527074a4fd3ba9d8b9ebc6db7 100644 (file)
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -88,6 +88,10 @@ PrintMachineInstrs("print-machineinstrs", cl::ValueOptional,
                    cl::desc("Print machine instrs"),
                    cl::value_desc("pass-name"), cl::init("option-unspecified"));
 
+// Experimental option to run live inteerval analysis early.
+static cl::opt<bool> EarlyLiveIntervals("early-live-intervals", cl::Hidden,
+    cl::desc("Run live interval analysis earlier in the pipeline"));
+
 /// Allow standard passes to be disabled by command line options. This supports
 /// simple binary flags that either suppress the pass or do nothing.
 /// i.e. -disable-mypass=false has no effect.
@@ -648,6 +652,11 @@ void TargetPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
     addPass(&MachineLoopInfoID);
     addPass(&PHIEliminationID);
   }
+
+  // Eventually, we want to run LiveIntervals before PHI elimination.
+  if (EarlyLiveIntervals)
+    addPass(&LiveIntervalsID);
+
   addPass(&TwoAddressInstructionPassID);
 
   if (EnableStrongPHIElim)