From c6bae79adb6a58be629804d058abb5613e561b5a Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Fri, 21 Jun 2013 18:33:23 +0000
Subject: [PATCH] Added -precompute-phys-liveness for testing LiveIntervals
 updates.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184573 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/LiveIntervalAnalysis.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 18eac4c7f96..368094396b0 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -52,6 +52,14 @@ INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
 INITIALIZE_PASS_END(LiveIntervals, "liveintervals",
                 "Live Interval Analysis", false, false)
 
+#ifndef NDEBUG
+static cl::opt<bool> EnablePrecomputePhysRegs(
+  "precompute-phys-liveness", cl::Hidden,
+  cl::desc("Eagerly compute live intervals for all physreg units."));
+#else
+static bool EnablePrecomputePhysRegs = false;
+#endif // NDEBUG
+
 void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
   AU.addRequired<AliasAnalysis>();
@@ -116,6 +124,12 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
   computeRegMasks();
   computeLiveInRegUnits();
 
+  if (EnablePrecomputePhysRegs) {
+    // For stress testing, precompute live ranges of all physical register
+    // units, including reserved registers.
+    for (unsigned i = 0, e = TRI->getNumRegUnits(); i != e; ++i)
+      getRegUnit(i);
+  }
   DEBUG(dump());
   return true;
 }