ART: Implement HSelect

This patch adds a new HIR instruction to Optimizing. HSelect returns
one of two inputs based on the outcome of a condition.

This is only initial implementation which:
 - defines the new instruction,
 - repurposes BooleanSimplifier to emit it,
 - extends InstructionSimplifier to statically resolve it,
 - updates existing code and tests accordingly.

Code generators currently emit fallback if/then/else code and will be
updated in follow-up CLs to use platform-specific conditional moves
when possible.

Change-Id: Ib61b17146487ebe6b55350c2b589f0b971dcaaee

1 files changed, 26 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index fec5811082..a2f85fe05c 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -3381,6 +3381,32 @@ void InstructionCodeGeneratorMIPS::VisitDeoptimize(HDeoptimize* deoptimize) {
                         /* false_target */ nullptr);
 }
 
+void LocationsBuilderMIPS::VisitSelect(HSelect* select) {
+  LocationSummary* locations = new (GetGraph()->GetArena()) LocationSummary(select);
+  if (Primitive::IsFloatingPointType(select->GetType())) {
+    locations->SetInAt(0, Location::RequiresFpuRegister());
+    locations->SetInAt(1, Location::RequiresFpuRegister());
+  } else {
+    locations->SetInAt(0, Location::RequiresRegister());
+    locations->SetInAt(1, Location::RequiresRegister());
+  }
+  if (IsBooleanValueOrMaterializedCondition(select->GetCondition())) {
+    locations->SetInAt(2, Location::RequiresRegister());
+  }
+  locations->SetOut(Location::SameAsFirstInput());
+}
+
+void InstructionCodeGeneratorMIPS::VisitSelect(HSelect* select) {
+  LocationSummary* locations = select->GetLocations();
+  MipsLabel false_target;
+  GenerateTestAndBranch(select,
+                        /* condition_input_index */ 2,
+                        /* true_target */ nullptr,
+                        &false_target);
+  codegen_->MoveLocation(locations->Out(), locations->InAt(1), select->GetType());
+  __ Bind(&false_target);
+}
+
 void LocationsBuilderMIPS::VisitNativeDebugInfo(HNativeDebugInfo* info) {
   new (GetGraph()->GetArena()) LocationSummary(info);
 }