From c9493317b8fc5ca3ec1adbf6f8a2f513110157cf Mon Sep 17 00:00:00 2001
From: Steve MacLean <sdmaclea.qdt@qualcommdatacenter.com>
Date: Tue, 12 Sep 2017 18:00:58 -0400
Subject: [PATCH] [Arm64] Enable Lowering GT_ARR_BOUNDS_CHECK

---
 src/jit/codegenarmarch.cpp | 11 ++++++++++-
 src/jit/lower.cpp          |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/jit/codegenarmarch.cpp b/src/jit/codegenarmarch.cpp
index 81bbb2aaa529..1cf3ec00b154 100644
--- a/src/jit/codegenarmarch.cpp
+++ b/src/jit/codegenarmarch.cpp
@@ -1225,7 +1225,16 @@ void CodeGen::genRangeCheck(GenTreePtr oper)
         jmpKind = genJumpKindForOper(GT_GE, CK_UNSIGNED);
     }
 
-    getEmitter()->emitInsBinary(INS_cmp, EA_4BYTE, src1, src2);
+    var_types bndsChkType = genActualType(src2->TypeGet());
+#if DEBUG
+    // Bounds checks can only be 32 or 64 bit sized comparisons.
+    assert(bndsChkType == TYP_INT || bndsChkType == TYP_LONG);
+
+    // The type of the bounds check should always wide enough to compare against the index.
+    assert(emitTypeSize(bndsChkType) >= emitTypeSize(genActualType(src1->TypeGet())));
+#endif // DEBUG
+
+    getEmitter()->emitInsBinary(INS_cmp, emitTypeSize(bndsChkType), src1, src2);
     genJumpToThrowHlpBlk(jmpKind, SCK_RNGCHK_FAIL, bndsChk->gtIndRngFailBB);
 }
 
diff --git a/src/jit/lower.cpp b/src/jit/lower.cpp
index 7c604053ec56..724d30b2e8ba 100644
--- a/src/jit/lower.cpp
+++ b/src/jit/lower.cpp
@@ -210,7 +210,7 @@ GenTree* Lowering::LowerNode(GenTree* node)
             LowerCast(node);
             break;
 
-#ifdef _TARGET_XARCH_
+#if defined(_TARGET_XARCH_) || defined(_TARGET_ARM64_)
         case GT_ARR_BOUNDS_CHECK:
 #ifdef FEATURE_SIMD
         case GT_SIMD_CHK: