Quick: Fix DCE, clear high word flag in RemoveChange().

Bug: 20640451

(cherry picked from commit ade58e14582c6ab81978e9cfcbbf5e54cc23fe18)

Change-Id: I8ac7fea3d9d2a434ee79fb917e68a4dc96e5482f

diff --git a/compiler/dex/gvn_dead_code_elimination.cc b/compiler/dex/gvn_dead_code_elimination.cc
index 6e1e414..915fbcd 100644 (file)
--- a/compiler/dex/gvn_dead_code_elimination.cc
+++ b/compiler/dex/gvn_dead_code_elimination.cc
@@ -340,7 +340,8 @@ void GvnDeadCodeElimination::VRegChains::RemoveChange(uint16_t change) {
       DCHECK_EQ(vreg_high_words_.IsBitSet(v_reg), v_reg == data->vreg_def + 1);
       if (data->vreg_def == v_reg && data->low_def_over_high_word) {
         vreg_high_words_.SetBit(v_reg);
-      } else if (data->vreg_def != v_reg && data->high_def_over_low_word) {
+      } else if (data->vreg_def != v_reg &&
+          (data->high_def_over_low_word || data->prev_value_high.value == kNoValue)) {
         vreg_high_words_.ClearBit(v_reg);
       }
     } else {