Intrinsify String.length() and String.isEmpty() as HIR.

Use HArrayLength for String.length() in anticipation of
changing the String.charAt() to HBoundsCheck+HArrayGet to
allow the existing BCE to seamlessly work for strings.
Use HArrayLength+HEqual for String.isEmpty().

We previously relied on inlining but we now want to apply
the new intrinsics even when we do not inline, i.e. when
compiling debuggable (as is currently the case for boot
image) or when we hit inlining limits, i.e. depth, size,
or the number of accumulated dex registers.

Bug: 28330359
Change-Id: Iab9d2f6d2967bdd930a72eb461f27efe8f37c103

1 files changed, 2 insertions, 4 deletions

diff --git a/compiler/optimizing/intrinsics.cc b/compiler/optimizing/intrinsics.cc
index 5d4c4e2950..418d59c6cb 100644
--- a/compiler/optimizing/intrinsics.cc
+++ b/compiler/optimizing/intrinsics.cc
@@ -388,10 +388,8 @@ static Intrinsics GetIntrinsic(InlineMethod method) {
     case kIntrinsicGetCharsNoCheck:
       return Intrinsics::kStringGetCharsNoCheck;
     case kIntrinsicIsEmptyOrLength:
-      // The inliner can handle these two cases - and this is the preferred approach
-      // since after inlining the call is no longer visible (as opposed to waiting
-      // until codegen to handle intrinsic).
-      return Intrinsics::kNone;
+      return ((method.d.data & kIntrinsicFlagIsEmpty) == 0) ?
+          Intrinsics::kStringLength : Intrinsics::kStringIsEmpty;
     case kIntrinsicIndexOf:
       return ((method.d.data & kIntrinsicFlagBase0) == 0) ?
           Intrinsics::kStringIndexOfAfter : Intrinsics::kStringIndexOf;