From d5be48a9db6bf9b1b399e1309b9654e06a616165 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Tue, 3 Apr 2012 16:27:16 +0000
Subject: [PATCH] Matrix simplification in PBQP may push infinite costs onto
 register options. The colorability heuristic should count these as denied
 registers.

No test case - this exposed a bug on an out-of-tree target.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153958 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/PBQP/Heuristics/Briggs.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/llvm/CodeGen/PBQP/Heuristics/Briggs.h b/include/llvm/CodeGen/PBQP/Heuristics/Briggs.h
index e96c4cb1e0c..a859e5899f0 100644
--- a/include/llvm/CodeGen/PBQP/Heuristics/Briggs.h
+++ b/include/llvm/CodeGen/PBQP/Heuristics/Briggs.h
@@ -418,6 +418,12 @@ namespace PBQP {
         unsigned numRegs = getGraph().getNodeCosts(nItr).getLength() - 1;
 
         nd.numDenied = 0;
+        const Vector& nCosts = getGraph().getNodeCosts(nItr);
+        for (unsigned i = 1; i < nCosts.getLength(); ++i) {
+          if (nCosts[i] == std::numeric_limits<PBQPNum>::infinity())
+            ++nd.numDenied;
+        }
+
         nd.numSafe = numRegs;
         nd.unsafeDegrees.resize(numRegs, 0);