ART: BitVector and Optimization changes
- The BitVector has a function SameBitsSet that is a bit upside down
- This patch fixes it.
- Two optimizations are fixed also:
- The null check pass uses now same bits set instead of equal due to a
subsequent change that will make it not always the case that the
compared bitvectors be of the same size.
- The fused optimization supposes a predecessor will have an instruction.
Change-Id: I9ef1c793964b18dc0f47baf9d1f361448bb053a3
Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>
Signed-off-by: Razvan A Lupusoru <razvan.a.lupusoru@intel.com>
Signed-off-by: Yixin Shou <yixin.shou@intel.com>
Signed-off-by: Chao-ying Fu <chao-ying.fu@intel.com>
Signed-off-by: Udayan Banerji <udayan.banerji@intel.com>
diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 5c1bdf4..9bd87f2 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -743,18 +743,20 @@
if (pred_bb->block_type == kDalvikByteCode) {
// Check to see if predecessor had an explicit null-check.
MIR* last_insn = pred_bb->last_mir_insn;
- Instruction::Code last_opcode = last_insn->dalvikInsn.opcode;
- if (last_opcode == Instruction::IF_EQZ) {
- if (pred_bb->fall_through == bb->id) {
- // The fall-through of a block following a IF_EQZ, set the vA of the IF_EQZ to show that
- // it can't be null.
- ssa_regs_to_check->ClearBit(last_insn->ssa_rep->uses[0]);
- }
- } else if (last_opcode == Instruction::IF_NEZ) {
- if (pred_bb->taken == bb->id) {
- // The taken block following a IF_NEZ, set the vA of the IF_NEZ to show that it can't be
- // null.
- ssa_regs_to_check->ClearBit(last_insn->ssa_rep->uses[0]);
+ if (last_insn != nullptr) {
+ Instruction::Code last_opcode = last_insn->dalvikInsn.opcode;
+ if (last_opcode == Instruction::IF_EQZ) {
+ if (pred_bb->fall_through == bb->id) {
+ // The fall-through of a block following a IF_EQZ, set the vA of the IF_EQZ to show that
+ // it can't be null.
+ ssa_regs_to_check->ClearBit(last_insn->ssa_rep->uses[0]);
+ }
+ } else if (last_opcode == Instruction::IF_NEZ) {
+ if (pred_bb->taken == bb->id) {
+ // The taken block following a IF_NEZ, set the vA of the IF_NEZ to show that it can't be
+ // null.
+ ssa_regs_to_check->ClearBit(last_insn->ssa_rep->uses[0]);
+ }
}
}
}
@@ -903,7 +905,7 @@
temp_scoped_alloc_.get(), temp_bit_vector_size_, false, kBitMapNullCheck);
nce_changed = ssa_regs_to_check->GetHighestBitSet() != -1;
bb->data_flow_info->ending_check_v->Copy(ssa_regs_to_check);
- } else if (!ssa_regs_to_check->Equal(bb->data_flow_info->ending_check_v)) {
+ } else if (!ssa_regs_to_check->SameBitsSet(bb->data_flow_info->ending_check_v)) {
nce_changed = true;
bb->data_flow_info->ending_check_v->Copy(ssa_regs_to_check);
}
diff --git a/runtime/base/bit_vector.cc b/runtime/base/bit_vector.cc
index 3df5101..980b1a6 100644
--- a/runtime/base/bit_vector.cc
+++ b/runtime/base/bit_vector.cc
@@ -113,23 +113,24 @@
// If the highest bit set is different, we are different.
if (our_highest != src_highest) {
- return true;
+ return false;
}
// If the highest bit set is -1, both are cleared, we are the same.
// If the highest bit set is 0, both have a unique bit set, we are the same.
- if (our_highest >= 0) {
+ if (our_highest <= 0) {
return true;
}
- // Get the highest bit set's cell's index.
- int our_highest_index = (our_highest >> 5);
+ // Get the highest bit set's cell's index
+ // No need of highest + 1 here because it can't be 0 so BitsToWords will work here.
+ int our_highest_index = BitsToWords(our_highest);
// This memcmp is enough: we know that the highest bit set is the same for both:
// - Therefore, min_size goes up to at least that, we are thus comparing at least what we need to, but not less.
// ie. we are comparing all storage cells that could have difference, if both vectors have cells above our_highest_index,
// they are automatically at 0.
- return (memcmp(storage_, src->GetRawStorage(), our_highest_index * sizeof(*storage_)) != 0);
+ return (memcmp(storage_, src->GetRawStorage(), our_highest_index * sizeof(*storage_)) == 0);
}
// Intersect with another bit vector.