Merge "[optimizing] Improve x86 parallel moves/swaps"

1 files changed, 24 insertions, 0 deletions

diff --git a/compiler/optimizing/parallel_move_resolver.cc b/compiler/optimizing/parallel_move_resolver.cc
index 9df8f5640d..4936685367 100644
--- a/compiler/optimizing/parallel_move_resolver.cc
+++ b/compiler/optimizing/parallel_move_resolver.cc
@@ -269,6 +269,20 @@ int ParallelMoveResolver::AllocateScratchRegister(int blocked,
 }
 
 
+int ParallelMoveResolver::AllocateScratchRegister(int blocked,
+                                                  int register_count) {
+  int scratch = -1;
+  for (int reg = 0; reg < register_count; ++reg) {
+    if ((blocked != reg) && IsScratchLocation(Location::RegisterLocation(reg))) {
+      scratch = reg;
+      break;
+    }
+  }
+
+  return scratch;
+}
+
+
 ParallelMoveResolver::ScratchRegisterScope::ScratchRegisterScope(
     ParallelMoveResolver* resolver, int blocked, int if_scratch, int number_of_registers)
     : resolver_(resolver),
@@ -282,6 +296,16 @@ ParallelMoveResolver::ScratchRegisterScope::ScratchRegisterScope(
 }
 
 
+ParallelMoveResolver::ScratchRegisterScope::ScratchRegisterScope(
+    ParallelMoveResolver* resolver, int blocked, int number_of_registers)
+    : resolver_(resolver),
+      reg_(kNoRegister),
+      spilled_(false) {
+  // We don't want to spill a register if none are free.
+  reg_ = resolver_->AllocateScratchRegister(blocked, number_of_registers);
+}
+
+
 ParallelMoveResolver::ScratchRegisterScope::~ScratchRegisterScope() {
   if (spilled_) {
     resolver_->RestoreScratch(reg_);