Index: llvm/include/llvm/LTO/legacy/LTOCodeGenerator.h
===================================================================
--- llvm/include/llvm/LTO/legacy/LTOCodeGenerator.h
+++ llvm/include/llvm/LTO/legacy/LTOCodeGenerator.h
@@ -230,6 +230,7 @@
   const Target *MArch = nullptr;
   std::string TripleStr;
   unsigned OptLevel = 2;
+  unsigned SizeLevel = 0;
   lto_diagnostic_handler_t DiagHandler = nullptr;
   void *DiagContext = nullptr;
   bool ShouldInternalize = EnableLTOInternalization;
Index: llvm/lib/LTO/LTOCodeGenerator.cpp
===================================================================
--- llvm/lib/LTO/LTOCodeGenerator.cpp
+++ llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -211,6 +211,10 @@
 }
 
 void LTOCodeGenerator::setOptLevel(unsigned Level) {
+  if (Level > 3) {
+    SizeLevel = Level - 3;
+    Level = 2;
+  }
   OptLevel = Level;
   switch (OptLevel) {
   case 0:
@@ -578,7 +582,7 @@
   PassManagerBuilder PMB;
   PMB.LoopVectorize = true;
   PMB.SLPVectorize = true;
-  PMB.Inliner = createFunctionInliningPass();
+  PMB.Inliner = createFunctionInliningPass(OptLevel, SizeLevel, false);
   PMB.LibraryInfo = new TargetLibraryInfoImpl(TargetTriple);
   if (Freestanding)
     PMB.LibraryInfo->disableAllFunctions();
Index: llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -985,8 +985,9 @@
 
   // Now that we internalized some globals, see if we can hack on them!
   PM.add(createGlobalOptimizerPass());
-  // Promote any localized global vars.
-  PM.add(createPromoteMemoryToRegisterPass());
+  // Break up allocas
+  PM.add(createSROAPass());
+  PM.add(createEarlyCSEPass());
 
   // Linking modules together can lead to duplicated global constants, only
   // keep one copy of each constant.
@@ -1039,9 +1040,6 @@
   addExtensionsToPM(EP_Peephole, PM);
   PM.add(createJumpThreadingPass(/*FreezeSelectCond*/ true));
 
-  // Break up allocas
-  PM.add(createSROAPass());
-
   // LTO provides additional opportunities for tailcall elimination due to
   // link-time inlining, and visibility of nocapture attribute.
   if (OptLevel > 1)
Index: llvm/tools/lto/lto.cpp
===================================================================
--- llvm/tools/lto/lto.cpp
+++ llvm/tools/lto/lto.cpp
@@ -152,8 +152,12 @@
     CG->setAttr(attrs);
   }
 
-  if (OptLevel < '0' || OptLevel > '3')
-    report_fatal_error("Optimization level must be between 0 and 3");
+  if (OptLevel == 's')
+    OptLevel = '4';
+  else if (OptLevel == 'z')
+    OptLevel = '5';
+  if (OptLevel < '0' || OptLevel > '5')
+    report_fatal_error("Optimization level must be between 0 and 3 or Os or Oz");
   CG->setOptLevel(OptLevel - '0');
   CG->setFreestanding(EnableFreestanding);
 }
@@ -502,8 +506,12 @@
   CodeGen->setFreestanding(EnableFreestanding);
 
   if (OptLevel.getNumOccurrences()) {
-    if (OptLevel < '0' || OptLevel > '3')
-      report_fatal_error("Optimization level must be between 0 and 3");
+    if (OptLevel == 's')
+      OptLevel = '4';
+    else if (OptLevel == 'z')
+      OptLevel = '5';
+    if (OptLevel < '0' || OptLevel > '5')
+      report_fatal_error("Optimization level must be between 0 and 3 or Os or Oz");
     CodeGen->setOptLevel(OptLevel - '0');
     switch (OptLevel) {
     case '0':