ART: Fix bug in LSE

LSE will not remove a load if the type of the heap value does not
match the type of the load. This was a workaround for b/22538329 but
backfires for integers. For example, 'IntConstant 0' has type int
but can be retrieved from a boolean field. The corresponding store is
removed but not the load, loading uninitialized memory. This fixes the
issue until the workaround is not needed any more.

Change-Id: I2a47783e8d5f93104854e5216b69b6c220832c76

1 files changed, 12 insertions, 1 deletions

diff --git a/compiler/optimizing/load_store_elimination.cc b/compiler/optimizing/load_store_elimination.cc
index adde00464b..2a2221a82c 100644
--- a/compiler/optimizing/load_store_elimination.cc
+++ b/compiler/optimizing/load_store_elimination.cc
@@ -655,6 +655,16 @@ class LSEVisitor : public HGraphVisitor {
     }
   }
 
+  static bool IsIntFloatAlias(Primitive::Type type1, Primitive::Type type2) {
+    return (type1 == Primitive::kPrimFloat && type2 == Primitive::kPrimInt) ||
+           (type2 == Primitive::kPrimFloat && type1 == Primitive::kPrimInt);
+  }
+
+  static bool IsLongDoubleAlias(Primitive::Type type1, Primitive::Type type2) {
+    return (type1 == Primitive::kPrimDouble && type2 == Primitive::kPrimLong) ||
+           (type2 == Primitive::kPrimDouble && type1 == Primitive::kPrimLong);
+  }
+
   void VisitGetLocation(HInstruction* instruction,
                         HInstruction* ref,
                         size_t offset,
@@ -686,7 +696,8 @@ class LSEVisitor : public HGraphVisitor {
     if ((heap_value != kUnknownHeapValue) &&
         // Keep the load due to possible I/F, J/D array aliasing.
         // See b/22538329 for details.
-        (heap_value->GetType() == instruction->GetType())) {
+        !IsIntFloatAlias(heap_value->GetType(), instruction->GetType()) &&
+        !IsLongDoubleAlias(heap_value->GetType(), instruction->GetType())) {
       removed_loads_.push_back(instruction);
       substitute_instructions_for_loads_.push_back(heap_value);
       TryRemovingNullCheck(instruction);