commit 11c9a325399b282cb4ea7d1d24d42fceeec2a09a
author Andrew Scull <ascull@google.com> Fri Aug 28 14:24:14 2015 -0700
committer Andrew Scull <ascull@google.com> Fri Aug 28 14:24:14 2015 -0700
tree 351ff0336a0789b72500fde2c83a9426a4e9ba3a
parent 25529f7bdaf3dfa08455b87642a120e84961d6d6

Weight variables for register allocation by their number of uses.

Count the number of instructions that use a variable following the heuristic
that more uses implies higher register priority. This is currently very simple
but is precursor work for weighting variables by loop nest depth.

BUG=
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/1312433004.

src/IceLiveness.cpp

diff --git a/src/IceLiveness.cpp b/src/IceLiveness.cpp
index 35e12b7..15877b2 100644
--- a/src/IceLiveness.cpp
+++ b/src/IceLiveness.cpp
@@ -102,7 +102,7 @@
     Variable *Var = *I;
     SizeT VarIndex = Var->getIndex();
     if (Var->getIgnoreLiveness() ||
-        (!IsFullInit && !Var->hasReg() && !Var->getWeight().isInf()))
+        (!IsFullInit && !Var->hasReg() && !Var->mustHaveReg()))
       RangeMask[VarIndex] = false;
   }