Compiler: stop wasting cycles....
Must have gotten carried away during the refactoring of the
graph traversal code... The quick codegen's mechanism to sum
the static uses of SSA regs and bucket them by parent Dalvik vreg
was getting run once for each basic block, when all it needed was
to be run once per method.
This had no effect on register allocation because the use counts
kept their relative position, but it uselessly wasted cycles.
Also fixed an inconsistency in the promotion threshold.
Change-Id: I58b438fe419f789ed11f7b136db645b2d23395de
diff --git a/src/compiler/dex/quick/mir_to_lir.h b/src/compiler/dex/quick/mir_to_lir.h
index d2d56f7..69ebc7e 100644
--- a/src/compiler/dex/quick/mir_to_lir.h
+++ b/src/compiler/dex/quick/mir_to_lir.h
@@ -360,8 +360,7 @@
RegLocation UpdateRawLoc(RegLocation loc);
RegLocation EvalLocWide(RegLocation loc, int reg_class, bool update);
RegLocation EvalLoc(RegLocation loc, int reg_class, bool update);
- void CountRefs(BasicBlock* bb, RefCounts* core_counts,
- RefCounts* fp_counts);
+ void CountRefs(RefCounts* core_counts, RefCounts* fp_counts);
void DumpCounts(const RefCounts* arr, int size, const char* msg);
void DoPromotion();
int VRegOffset(int v_reg);
diff --git a/src/compiler/dex/quick/ralloc_util.cc b/src/compiler/dex/quick/ralloc_util.cc
index a89cfa8..a6b8793 100644
--- a/src/compiler/dex/quick/ralloc_util.cc
+++ b/src/compiler/dex/quick/ralloc_util.cc
@@ -1000,15 +1000,7 @@
}
/* USE SSA names to count references of base Dalvik v_regs. */
-void Mir2Lir::CountRefs(BasicBlock* bb, RefCounts* core_counts,
- RefCounts* fp_counts)
-{
- // TUNING: this routine could use some tweaking.
- if ((cu_->disable_opt & (1 << kPromoteRegs)) ||
- !((bb->block_type == kEntryBlock) || (bb->block_type == kExitBlock) ||
- (bb->block_type == kDalvikByteCode))) {
- return;
- }
+void Mir2Lir::CountRefs(RefCounts* core_counts, RefCounts* fp_counts) {
for (int i = 0; i < mir_graph_->GetNumSSARegs(); i++) {
RegLocation loc = mir_graph_->reg_location_[i];
RefCounts* counts = loc.fp ? fp_counts : core_counts;
@@ -1048,7 +1040,7 @@
int reg_bias = cu_->num_compiler_temps + 1;
int dalvik_regs = cu_->num_dalvik_registers;
int num_regs = dalvik_regs + reg_bias;
- const int promotion_threshold = 2;
+ const int promotion_threshold = 1;
// Allow target code to add any special registers
AdjustSpillMask();
@@ -1082,13 +1074,8 @@
FpRegs[dalvik_regs + i].s_reg = ct->s_reg;
}
- GrowableListIterator iterator = mir_graph_->GetBasicBlockIterator();
- while (true) {
- BasicBlock* bb;
- bb = reinterpret_cast<BasicBlock*>(GrowableListIteratorNext(&iterator));
- if (bb == NULL) break;
- CountRefs(bb, core_regs, FpRegs);
- }
+ // Sum use counts of SSA regs by original Dalvik vreg.
+ CountRefs(core_regs, FpRegs);
/*
* Ideally, we'd allocate doubles starting with an even-numbered
@@ -1126,7 +1113,7 @@
// Promote core regs
for (int i = 0; (i < num_regs) &&
- (core_regs[i].count > promotion_threshold); i++) {
+ (core_regs[i].count >= promotion_threshold); i++) {
int p_map_idx = SRegToPMap(core_regs[i].s_reg);
if (promotion_map_[p_map_idx].core_location !=
kLocPhysReg) {
