commit 877b04e409637216712d3c36fc155b47f8bd8d38
author Jim Stichnoth <stichnot@chromium.org> Wed Oct 15 15:13:06 2014 -0700
committer Jim Stichnoth <stichnot@chromium.org> Wed Oct 15 15:13:06 2014 -0700
tree e2d4b771552980b2928fb18a7b13f627981dac63
parent 7b451a928d91d1c38805c7a53e18519000fe7c42

Subzero: Speed up VariablesMetadata initialization.

Currently, O2 calls VariablesMetadata::init() 4 times:

- Twice for liveness analysis, where only multi-block use information is needed for dealing with sparse bit vectors.

- Once for address mode inference, where single-definition information is needed.

- Once for register allocation, where all information is needed, including the set of all definitions which is needed for determining AllowOverlap.

So we limit the amount of data we gather based on the actual need.

BUG= none
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/650613003

src/IceTargetLoweringX8632.cpp

diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index dfb1fda..232acdd 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -329,7 +329,7 @@
   Func->dump("After Phi lowering");
 
   // Address mode optimization.
-  Func->getVMetadata()->init();
+  Func->getVMetadata()->init(VMK_SingleDefs);
   Func->doAddressOpt();
 
   // Argument lowering
@@ -372,7 +372,7 @@
   // The post-codegen dump is done here, after liveness analysis and
   // associated cleanup, to make the dump cleaner and more useful.
   Func->dump("After initial x8632 codegen");
-  Func->getVMetadata()->init();
+  Func->getVMetadata()->init(VMK_All);
   regAlloc();
   if (Func->hasError())
     return;