Avoid move to same registers.

We do always use ints as W registers.

Test: test.py
Change-Id: I9743edf2fd7bacba036b41fda42bdd539264a73c

1 files changed, 1 insertions, 6 deletions

diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 42d955ef9e..ef2d67334a 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -6644,12 +6644,7 @@ void InstructionCodeGeneratorARM64::VisitTypeConversion(HTypeConversion* convers
     if (result_type == DataType::Type::kInt32 && input_type == DataType::Type::kInt64) {
       // 'int' values are used directly as W registers, discarding the top
       // bits, so we don't need to sign-extend and can just perform a move.
-      // We do not pass the `kDiscardForSameWReg` argument to force clearing the
-      // top 32 bits of the target register. We theoretically could leave those
-      // bits unchanged, but we would have to make sure that no code uses a
-      // 32bit input value as a 64bit value assuming that the top 32 bits are
-      // zero.
-      __ Mov(output.W(), source.W());
+      __ Mov(output.W(), source.W(), kDiscardForSameWReg);
     } else if (DataType::IsUnsignedType(result_type) ||
                (DataType::IsUnsignedType(input_type) && input_size < result_size)) {
       __ Ubfx(output, output.IsX() ? source.X() : source.W(), 0, result_size * kBitsPerByte);