ARM64: Share address computation across SIMD LDRs/STRs.

For array accesses the element address has the following structure:
Address = CONST_OFFSET + base_addr + index << ELEM_SHIFT

Taking into account ARM64 LDR/STR addressing modes address part
(CONST_OFFSET + index << ELEM_SHIFT) can be shared across array
access with the same data type and index.

For example, for the following loop 5 accesses can share address
computation:

void foo(int[] a, int[] b, int[] c) {
  for (i...) {
    a[i] = a[i] + 5;
    b[i] = b[i] + c[i];
  }
}

Test: test-art-host, test-art-target

Change-Id: I46af3b4e4a55004336672cdba3296b7622d815ca

1 files changed, 6 insertions, 1 deletions

diff --git a/compiler/optimizing/nodes_vector.h b/compiler/optimizing/nodes_vector.h
index 52c247b52f..92fe9bfa7d 100644
--- a/compiler/optimizing/nodes_vector.h
+++ b/compiler/optimizing/nodes_vector.h
@@ -178,12 +178,17 @@ class HVecMemoryOperation : public HVecOperation {
                       size_t vector_length,
                       uint32_t dex_pc)
       : HVecOperation(arena, packed_type, side_effects, number_of_inputs, vector_length, dex_pc),
-        alignment_(Primitive::ComponentSize(packed_type), 0) { }
+        alignment_(Primitive::ComponentSize(packed_type), 0) {
+    DCHECK_GE(number_of_inputs, 2u);
+  }
 
   void SetAlignment(Alignment alignment) { alignment_ = alignment; }
 
   Alignment GetAlignment() const { return alignment_; }
 
+  HInstruction* GetArray() const { return InputAt(0); }
+  HInstruction* GetIndex() const { return InputAt(1); }
+
   DECLARE_ABSTRACT_INSTRUCTION(VecMemoryOperation);
 
  private: