ART: Implement HBooleanNot instruction

Optimizations simplifying operations on boolean values (boolean
simplifier, instruction simplifier) can benefit from having a special
HInstruction for negating booleans in order to perform more transforms
and produce faster machine code.

This patch implements HBooleanNot as 'x xor 1', assuming that booleans
are 1-bit integers and allowing for a single-instruction negation on
all supported platforms.

Change-Id: I33a2649c1821255b18a86ca68ed16416063c739f

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/optimizing/boolean_simplifier.cc b/compiler/optimizing/boolean_simplifier.cc
index be432c5a20..06328f2490 100644
--- a/compiler/optimizing/boolean_simplifier.cc
+++ b/compiler/optimizing/boolean_simplifier.cc
@@ -73,8 +73,8 @@ static HInstruction* GetOppositeCondition(HInstruction* cond) {
     }
   } else {
     // General case when 'cond' is another instruction of type boolean.
-    // Negate with 'cond == 0'.
-    return new (allocator) HEqual(cond, graph->GetIntConstant(0));
+    DCHECK_EQ(cond->GetType(), Primitive::Type::kPrimBoolean);
+    return new (allocator) HBooleanNot(cond);
   }
 }