[llvm] r315043 - [PM] Retire disable unit-at-a-time switch.

[Davide Italiano via llvm-commits]

Author: davide
Date: Thu Oct  5 21:39:40 2017
New Revision: 315043

URL: http://llvm.org/viewvc/llvm-project?rev=315043&view=rev
Log:
[PM] Retire disable unit-at-a-time switch.

This is a vestige from the GCC-3 days, which disables IPO passes
when set. I don't think anybody actually uses it as there are
several IPO passes which still run with this flag set and
nobody complained/noticed. This reduces the delta between
current and new pass manager and allows us to easily review
the difference when we decide to flip the switch (or audit
which passes should run, FWIW).

Modified:
    llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp

Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=315043&r1=315042&r2=315043&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu Oct  5 21:39:40 2017
@@ -151,7 +151,6 @@ PassManagerBuilder::PassManagerBuilder()
     SizeLevel = 0;
     LibraryInfo = nullptr;
     Inliner = nullptr;
-    DisableUnitAtATime = false;
     DisableUnrollLoops = false;
     SLPVectorize = RunSLPVectorization;
     LoopVectorize = RunLoopVectorization;
@@ -455,23 +454,21 @@ void PassManagerBuilder::populateModuleP
   if (PrepareForThinLTOUsingPGOSampleProfile)
     DisableUnrollLoops = true;
 
-  if (!DisableUnitAtATime) {
-    // Infer attributes about declarations if possible.
-    MPM.add(createInferFunctionAttrsLegacyPass());
+  // Infer attributes about declarations if possible.
+  MPM.add(createInferFunctionAttrsLegacyPass());
 
-    addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
+  addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
 
-    MPM.add(createIPSCCPPass());          // IP SCCP
-    MPM.add(createGlobalOptimizerPass()); // Optimize out global vars
-    // Promote any localized global vars.
-    MPM.add(createPromoteMemoryToRegisterPass());
+  MPM.add(createIPSCCPPass());          // IP SCCP
+  MPM.add(createGlobalOptimizerPass()); // Optimize out global vars
+  // Promote any localized global vars.
+  MPM.add(createPromoteMemoryToRegisterPass());
 
-    MPM.add(createDeadArgEliminationPass()); // Dead argument elimination
+  MPM.add(createDeadArgEliminationPass()); // Dead argument elimination
 
-    addInstructionCombiningPass(MPM); // Clean up after IPCP & DAE
-    addExtensionsToPM(EP_Peephole, MPM);
-    MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE
-  }
+  addInstructionCombiningPass(MPM); // Clean up after IPCP & DAE
+  addExtensionsToPM(EP_Peephole, MPM);
+  MPM.add(createCFGSimplificationPass()); // Clean up after IPCP & DAE
 
   // For SamplePGO in ThinLTO compile phase, we do not want to do indirect
   // call promotion as it will change the CFG too much to make the 2nd
@@ -487,16 +484,15 @@ void PassManagerBuilder::populateModuleP
   MPM.add(createGlobalsAAWrapperPass());
 
   // Start of CallGraph SCC passes.
-  if (!DisableUnitAtATime)
-    MPM.add(createPruneEHPass()); // Remove dead EH info
+  MPM.add(createPruneEHPass()); // Remove dead EH info
   bool RunInliner = false;
   if (Inliner) {
     MPM.add(Inliner);
     Inliner = nullptr;
     RunInliner = true;
   }
-  if (!DisableUnitAtATime)
-    MPM.add(createPostOrderFunctionAttrsLegacyPass());
+
+  MPM.add(createPostOrderFunctionAttrsLegacyPass());
   if (OptLevel > 2)
     MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args
 
@@ -511,8 +507,7 @@ void PassManagerBuilder::populateModuleP
   if (RunPartialInlining)
     MPM.add(createPartialInliningPass());
 
-  if (!DisableUnitAtATime && OptLevel > 1 && !PrepareForLTO &&
-      !PrepareForThinLTO)
+  if (OptLevel > 1 && !PrepareForLTO && !PrepareForThinLTO)
     // Remove avail extern fns and globals definitions if we aren't
     // compiling an object file for later LTO. For LTO we want to preserve
     // these so they are eligible for inlining at link-time. Note if they
@@ -524,8 +519,7 @@ void PassManagerBuilder::populateModuleP
     // and saves running remaining passes on the eliminated functions.
     MPM.add(createEliminateAvailableExternallyPass());
 
-  if (!DisableUnitAtATime)
-    MPM.add(createReversePostOrderFunctionAttrsPass());
+  MPM.add(createReversePostOrderFunctionAttrsPass());
 
   // The inliner performs some kind of dead code elimination as it goes,
   // but there are cases that are not really caught by it. We might
@@ -650,16 +644,14 @@ void PassManagerBuilder::populateModuleP
   // about pointer alignments.
   MPM.add(createAlignmentFromAssumptionsPass());
 
-  if (!DisableUnitAtATime) {
-    // FIXME: We shouldn't bother with this anymore.
-    MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
-
-    // GlobalOpt already deletes dead functions and globals, at -O2 try a
-    // late pass of GlobalDCE.  It is capable of deleting dead cycles.
-    if (OptLevel > 1) {
-      MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
-      MPM.add(createConstantMergePass());     // Merge dup global constants
-    }
+  // FIXME: We shouldn't bother with this anymore.
+  MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
+
+  // GlobalOpt already deletes dead functions and globals, at -O2 try a
+  // late pass of GlobalDCE.  It is capable of deleting dead cycles.
+  if (OptLevel > 1) {
+    MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
+    MPM.add(createConstantMergePass());     // Merge dup global constants
   }
 
   if (MergeFunctions)
@@ -941,8 +933,7 @@ LLVMPassManagerBuilderSetSizeLevel(LLVMP
 void
 LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
                                             LLVMBool Value) {
-  PassManagerBuilder *Builder = unwrap(PMB);
-  Builder->DisableUnitAtATime = Value;
+  // NOTE: The DisableUnitAtATime switch has been removed.
 }
 
 void