From aa1a1580eee610d9b9e432e0ccbe96d14c3fb811 Mon Sep 17 00:00:00 2001
From: William Chen <william.chen@futurewei.com>
Date: Thu, 18 Nov 2021 15:53:54 -0800
Subject: [PATCH] Use option --ret-merge to combine all return bb into one
 destination.

---
 src/mapleall/maple_be/include/cg/cg_option.h | 13 +++++++++++++
 src/mapleall/maple_be/src/cg/cg_option.cpp   | 15 +++++++++++++++
 src/mapleall/maple_be/src/cg/cgfunc.cpp      |  2 +-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/mapleall/maple_be/include/cg/cg_option.h b/src/mapleall/maple_be/include/cg/cg_option.h
index 10733c709f..4c9556941d 100644
--- a/src/mapleall/maple_be/include/cg/cg_option.h
+++ b/src/mapleall/maple_be/include/cg/cg_option.h
@@ -773,6 +773,18 @@ class CGOptions : public MapleDriverOptionBase {
     return doPeephole;
   }
 
+  static void EnableRetMerge() {
+    doRetMerge = true;
+  }
+
+  static void DisableRetMerge() {
+    doRetMerge = false;
+  }
+
+  static bool DoRetMerge() {
+    return doRetMerge;
+  }
+
   static void EnablePreSchedule() {
     doPreSchedule = true;
   }
@@ -1155,6 +1167,7 @@ class CGOptions : public MapleDriverOptionBase {
   static bool doMultiPassColorRA;
   static bool doPrePeephole;
   static bool doPeephole;
+  static bool doRetMerge;
   static bool doSchedule;
   static bool doAlignAnalysis;
   static bool doWriteRefFieldOpt;
diff --git a/src/mapleall/maple_be/src/cg/cg_option.cpp b/src/mapleall/maple_be/src/cg/cg_option.cpp
index 8679ba207a..9eb35c144d 100644
--- a/src/mapleall/maple_be/src/cg/cg_option.cpp
+++ b/src/mapleall/maple_be/src/cg/cg_option.cpp
@@ -70,6 +70,7 @@ bool CGOptions::doVregRename = false;
 bool CGOptions::doMultiPassColorRA = true;
 bool CGOptions::doPrePeephole = false;
 bool CGOptions::doPeephole = false;
+bool CGOptions::doRetMerge = false;
 bool CGOptions::doSchedule = false;
 bool CGOptions::doWriteRefFieldOpt = false;
 bool CGOptions::dumpOptimizeCommonLog = false;
@@ -126,6 +127,7 @@ enum OptionIndex : uint64 {
   kPeep,
   kPreSchedule,
   kSchedule,
+  kRetMerge,
   kVregRename,
   kMultiPassRA,
   kWriteRefFieldOpt,
@@ -432,6 +434,16 @@ const Descriptor kUsage[] = {
     "  --no-schedule\n",
     "mplcg",
     {} },
+  { kRetMerge,
+    kEnable,
+    "",
+    "ret-merge",
+    kBuildTypeExperimental,
+    kArgCheckPolicyBool,
+    "  --ret-merge                 \tMerge return bb into a single destination\n"
+    "  --no-ret-merge              \tallows for multiple return bb\n",
+    "mplcg",
+    {} },
   { kVregRename,
     kEnable,
     "",
@@ -1388,6 +1400,9 @@ bool CGOptions::SolveOptions(const std::vector<Option> &opts, bool isDebug) {
       case kPeep:
         (opt.Type() == kEnable) ? EnablePeephole() : DisablePeephole();
         break;
+      case kRetMerge:
+        (opt.Type() == kEnable) ? EnableRetMerge() : DisableRetMerge();
+        break;
       case kPreSchedule:
         (opt.Type() == kEnable) ? EnablePreSchedule() : DisablePreSchedule();
         break;
diff --git a/src/mapleall/maple_be/src/cg/cgfunc.cpp b/src/mapleall/maple_be/src/cg/cgfunc.cpp
index f497ce51fc..4e690f320b 100644
--- a/src/mapleall/maple_be/src/cg/cgfunc.cpp
+++ b/src/mapleall/maple_be/src/cg/cgfunc.cpp
@@ -1690,7 +1690,7 @@ void CGFunc::HandleFunction() {
   /* select instruction */
   GenerateInstruction();
   /* merge multi return */
-  if (!func.GetModule()->IsCModule()) {
+  if (!func.GetModule()->IsCModule() || CGOptions::DoRetMerge()) {
     MergeReturn();
   }
   if (func.IsJava()) {
-- 
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