From c21da273fe448f235b3e5ed0c9997cda8c2b343d Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <jonas.paulsson@ericsson.com>
Date: Mon, 16 Feb 2015 15:39:26 +0000
Subject: [PATCH] [PBQP] Improve the assert for conservatively allocatables.

Remember if the node ever was in this state instead of checking just the
final state.

Reviewed by Arnaud de Grandmaison.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229400 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/PBQP/ReductionRules.h |  2 +-
 include/llvm/CodeGen/RegAllocPBQP.h        | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/include/llvm/CodeGen/PBQP/ReductionRules.h b/include/llvm/CodeGen/PBQP/ReductionRules.h
index dae7da4ac9f..8f54ec93dd2 100644
--- a/include/llvm/CodeGen/PBQP/ReductionRules.h
+++ b/include/llvm/CodeGen/PBQP/ReductionRules.h
@@ -190,7 +190,7 @@ namespace PBQP {
       // Although a conservatively allocatable node can be allocated to a register,
       // spilling it may provide a lower cost solution. Assert here that spilling
       // is done by choice, not because there were no register available.
-      if (G.getNodeMetadata(NId).isConservativelyAllocatable())
+      if (G.getNodeMetadata(NId).wasConservativelyAllocatable())
         assert(hasRegisterOptions(v) && "A conservatively allocatable node "
                                         "must have available register options");
 
diff --git a/include/llvm/CodeGen/RegAllocPBQP.h b/include/llvm/CodeGen/RegAllocPBQP.h
index 6d709d2b5e0..a117eb070f0 100644
--- a/include/llvm/CodeGen/RegAllocPBQP.h
+++ b/include/llvm/CodeGen/RegAllocPBQP.h
@@ -192,7 +192,7 @@ public:
 
   NodeMetadata()
     : RS(Unprocessed), NumOpts(0), DeniedOpts(0), OptUnsafeEdges(nullptr),
-      VReg(0) {}
+      VReg(0), everConservativelyAllocatable(false) {}
 
   // FIXME: Re-implementing default behavior to work around MSVC. Remove once
   // MSVC synthesizes move constructors properly.
@@ -256,8 +256,14 @@ public:
   void setReductionState(ReductionState RS) {
     assert(RS >= this->RS && "A node's reduction state can not be downgraded");
     this->RS = RS;
+
+    // Remember this state to assert later that a non-infinite register
+    // option was available.
+    if (RS == ConservativelyAllocatable)
+      everConservativelyAllocatable = true;
   }
 
+
   void handleAddEdge(const MatrixMetadata& MD, bool Transpose) {
     DeniedOpts += Transpose ? MD.getWorstRow() : MD.getWorstCol();
     const bool* UnsafeOpts =
@@ -280,6 +286,10 @@ public:
        &OptUnsafeEdges[NumOpts]);
   }
 
+  bool wasConservativelyAllocatable() const {
+    return everConservativelyAllocatable;
+  }
+
 private:
   ReductionState RS;
   unsigned NumOpts;
@@ -287,6 +297,7 @@ private:
   std::unique_ptr<unsigned[]> OptUnsafeEdges;
   unsigned VReg;
   GraphMetadata::AllowedRegVecRef AllowedRegs;
+  bool everConservativelyAllocatable;
 };
 
 class RegAllocSolverImpl {
-- 
2.34.1