From 05b644ee6220e06b4b294a44d5ff0959603733d2 Mon Sep 17 00:00:00 2001
From: William Chen <william.chen@futurewei.com>
Date: Wed, 6 Jul 2022 10:15:51 -0700
Subject: [PATCH] Turn off rematerialization for lmbc.  Merge return bb for
 small C functions.

---
 src/mapleall/maple_be/include/cg/cgfunc.h     |  1 +
 .../src/cg/aarch64/aarch64_color_ra.cpp       | 20 +++++++++++--------
 src/mapleall/maple_be/src/cg/cgbb.cpp         |  1 +
 src/mapleall/maple_be/src/cg/cgfunc.cpp       |  3 ++-
 4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/mapleall/maple_be/include/cg/cgfunc.h b/src/mapleall/maple_be/include/cg/cgfunc.h
index b678bf79e4..d5707e66c9 100644
--- a/src/mapleall/maple_be/include/cg/cgfunc.h
+++ b/src/mapleall/maple_be/include/cg/cgfunc.h
@@ -81,6 +81,7 @@ class SpillMemOperandSet {
 class LiveRange;
 #endif  /* TARGARM32 */
 constexpr uint32 kVRegisterNumber = 80;
+constexpr uint32 kNumBBOptReturn = 30;
 class CGFunc {
  public:
   enum ShiftDirection : uint8 {
diff --git a/src/mapleall/maple_be/src/cg/aarch64/aarch64_color_ra.cpp b/src/mapleall/maple_be/src/cg/aarch64/aarch64_color_ra.cpp
index f3b666c4f1..c0b4bf5050 100644
--- a/src/mapleall/maple_be/src/cg/aarch64/aarch64_color_ra.cpp
+++ b/src/mapleall/maple_be/src/cg/aarch64/aarch64_color_ra.cpp
@@ -455,14 +455,18 @@ void GraphColorRegAllocator::CalculatePriority(LiveRange &lr) const {
   auto *a64CGFunc = static_cast<AArch64CGFunc*>(cgFunc);
   CG *cg = a64CGFunc->GetCG();
 
-  if (cg->GetRematLevel() >= rematConst && lr.IsRematerializable(*a64CGFunc, rematConst)) {
-    lr.SetRematLevel(rematConst);
-  } else if (cg->GetRematLevel() >= rematAddr && lr.IsRematerializable(*a64CGFunc, rematAddr)) {
-    lr.SetRematLevel(rematAddr);
-  } else if (cg->GetRematLevel() >= rematDreadLocal && lr.IsRematerializable(*a64CGFunc, rematDreadLocal)) {
-    lr.SetRematLevel(rematDreadLocal);
-  } else if (cg->GetRematLevel() >= rematDreadGlobal && lr.IsRematerializable(*a64CGFunc, rematDreadGlobal)) {
-    lr.SetRematLevel(rematDreadGlobal);
+  if (cgFunc->GetCG()->IsLmbc()) {
+    lr.SetRematLevel(rematOff);
+  } else {
+    if (cg->GetRematLevel() >= rematConst && lr.IsRematerializable(*a64CGFunc, rematConst)) {
+      lr.SetRematLevel(rematConst);
+    } else if (cg->GetRematLevel() >= rematAddr && lr.IsRematerializable(*a64CGFunc, rematAddr)) {
+      lr.SetRematLevel(rematAddr);
+    } else if (cg->GetRematLevel() >= rematDreadLocal && lr.IsRematerializable(*a64CGFunc, rematDreadLocal)) {
+      lr.SetRematLevel(rematDreadLocal);
+    } else if (cg->GetRematLevel() >= rematDreadGlobal && lr.IsRematerializable(*a64CGFunc, rematDreadGlobal)) {
+      lr.SetRematLevel(rematDreadGlobal);
+    }
   }
 
   auto calculatePriorityFunc = [&lr, &bbNum, &numDefs, &numUses, &pri, this] (uint32 bbID) {
diff --git a/src/mapleall/maple_be/src/cg/cgbb.cpp b/src/mapleall/maple_be/src/cg/cgbb.cpp
index 502983b519..d8b5e86278 100644
--- a/src/mapleall/maple_be/src/cg/cgbb.cpp
+++ b/src/mapleall/maple_be/src/cg/cgbb.cpp
@@ -525,6 +525,7 @@ void Bfs::ComputeBlockOrder() {
         done = true;
       } else {
         LogInfo::MapleLogger() << "Error: RA BFS loop " << sortedCnt << " in func " << cgfunc->GetName() << "\n";
+        CHECK_FATAL(false, "");
       }
     }
     sortedCnt = sortedBBs.size();
diff --git a/src/mapleall/maple_be/src/cg/cgfunc.cpp b/src/mapleall/maple_be/src/cg/cgfunc.cpp
index 788a763a8e..c31731265a 100644
--- a/src/mapleall/maple_be/src/cg/cgfunc.cpp
+++ b/src/mapleall/maple_be/src/cg/cgfunc.cpp
@@ -2074,7 +2074,8 @@ void CGFunc::HandleFunction() {
   /* select instruction */
   GenerateInstruction();
   /* merge multi return */
-  if (!func.GetModule()->IsCModule() || CGOptions::DoRetMerge() || CGOptions::OptimizeForSize()) {
+  if (!func.GetModule()->IsCModule() || (func.GetModule()->IsCModule() && (NumBBs() < kNumBBOptReturn)) ||
+      CGOptions::DoRetMerge() || CGOptions::OptimizeForSize()) {
     MergeReturn();
   }
   if (func.IsJava()) {
-- 
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