2 files changed, 35 insertions, 59 deletions
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index b22921b2b87..5896dbf5bb9 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -400,25 +400,21 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   FPM.addPass(EarlyCSEPass(true /* Enable mem-ssa. */));
 
   // Hoisting of scalars and load expressions.
-  if (Level > O1) {
-    if (EnableGVNHoist)
-      FPM.addPass(GVNHoistPass());
-
-    // Global value numbering based sinking.
-    if (EnableGVNSink) {
-      FPM.addPass(GVNSinkPass());
-      FPM.addPass(SimplifyCFGPass());
-    }
+  if (EnableGVNHoist)
+    FPM.addPass(GVNHoistPass());
+
+  // Global value numbering based sinking.
+  if (EnableGVNSink) {
+    FPM.addPass(GVNSinkPass());
+    FPM.addPass(SimplifyCFGPass());
   }
 
   // Speculative execution if the target has divergent branches; otherwise nop.
-  if (Level > O1) {
-    FPM.addPass(SpeculativeExecutionPass());
+  FPM.addPass(SpeculativeExecutionPass());
 
-    // Optimize based on known information about branches, and cleanup afterward.
-    FPM.addPass(JumpThreadingPass());
-    FPM.addPass(CorrelatedValuePropagationPass());
-  }
+  // Optimize based on known information about branches, and cleanup afterward.
+  FPM.addPass(JumpThreadingPass());
+  FPM.addPass(CorrelatedValuePropagationPass());
   FPM.addPass(SimplifyCFGPass());
   if (Level == O3)
     FPM.addPass(AggressiveInstCombinePass());
@@ -432,12 +428,10 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   // For PGO use pipeline, try to optimize memory intrinsics such as memcpy
   // using the size value profile. Don't perform this when optimizing for size.
   if (PGOOpt && PGOOpt->Action == PGOOptions::IRUse &&
-      !isOptimizingForSize(Level) && Level > O1)
+      !isOptimizingForSize(Level))
     FPM.addPass(PGOMemOPSizeOpt());
 
-  // TODO: Investigate the cost/benefit of tail call elimination on debugging.
-  if (Level > O1)
-    FPM.addPass(TailCallElimPass());
+  FPM.addPass(TailCallElimPass());
   FPM.addPass(SimplifyCFGPass());
 
   // Form canonically associated expression trees, and simplify the trees using
@@ -464,7 +458,6 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
 
   // Rotate Loop - disable header duplication at -Oz
   LPM1.addPass(LoopRotatePass(Level != Oz));
-  // TODO: Investigate promotion cap for O1.
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap));
   LPM1.addPass(SimpleLoopUnswitchPass());
   LPM2.addPass(IndVarSimplifyPass());
@@ -532,21 +525,18 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
 
   // Re-consider control flow based optimizations after redundancy elimination,
   // redo DCE, etc.
-  if (Level > O1) {
-    FPM.addPass(JumpThreadingPass());
-    FPM.addPass(CorrelatedValuePropagationPass());
-    FPM.addPass(DSEPass());
-    FPM.addPass(createFunctionToLoopPassAdaptor(
-        LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap),
-        EnableMSSALoopDependency, DebugLogging));
-  }
+  FPM.addPass(JumpThreadingPass());
+  FPM.addPass(CorrelatedValuePropagationPass());
+  FPM.addPass(DSEPass());
+  FPM.addPass(createFunctionToLoopPassAdaptor(
+      LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap),
+      EnableMSSALoopDependency, DebugLogging));
 
   for (auto &C : ScalarOptimizerLateEPCallbacks)
     C(FPM, Level);
 
   // Finally, do an expensive DCE pass to catch all the dead code exposed by
   // the simplifications and basic cleanup after all the simplifications.
-  // TODO: Investigate if this is too expensive.
   FPM.addPass(ADCEPass());
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 81424229c3b..5314a8219b1 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -320,26 +320,19 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
     legacy::PassManagerBase &MPM) {
   // Start of function pass.
   // Break up aggregate allocas, using SSAUpdater.
-  assert(OptLevel >= 1 && "Calling function optimizer with no optimization level!");
   MPM.add(createSROAPass());
   MPM.add(createEarlyCSEPass(true /* Enable mem-ssa. */)); // Catch trivial redundancies
-
-  if (OptLevel > 1) {
-    if (EnableGVNHoist)
-      MPM.add(createGVNHoistPass());
-    if (EnableGVNSink) {
-      MPM.add(createGVNSinkPass());
-      MPM.add(createCFGSimplificationPass());
-    }
+  if (EnableGVNHoist)
+    MPM.add(createGVNHoistPass());
+  if (EnableGVNSink) {
+    MPM.add(createGVNSinkPass());
+    MPM.add(createCFGSimplificationPass());
   }
 
-  if (OptLevel > 1) {
-    // Speculative execution if the target has divergent branches; otherwise nop.
-    MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
-
-    MPM.add(createJumpThreadingPass());         // Thread jumps.
-    MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
-  }
+  // Speculative execution if the target has divergent branches; otherwise nop.
+  MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
+  MPM.add(createJumpThreadingPass());         // Thread jumps.
+  MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
   // Combine silly seq's
   if (OptLevel > 2)
@@ -353,10 +346,8 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
   if (SizeLevel == 0)
     MPM.add(createPGOMemOPSizeOptLegacyPass());
 
-  // TODO: Investigate the cost/benefit of tail call elimination on debugging.
-  if (OptLevel > 1)
-    MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
-  MPM.add(createCFGSimplificationPass());      // Merge & remove BBs
+  MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
+  MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
   MPM.add(createReassociatePass());           // Reassociate expressions
 
   // Begin the loop pass pipeline.
@@ -369,7 +360,6 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
   }
   // Rotate Loop - disable header duplication at -Oz
   MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1));
-  // TODO: Investigate promotion cap for O1.
   MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
   if (EnableSimpleLoopUnswitch)
     MPM.add(createSimpleLoopUnswitchLegacyPass());
@@ -412,19 +402,16 @@ void PassManagerBuilder::addFunctionSimplificationPasses(
   // opened up by them.
   addInstructionCombiningPass(MPM);
   addExtensionsToPM(EP_Peephole, MPM);
-  if (OptLevel > 1) {
-    MPM.add(createJumpThreadingPass());         // Thread jumps
-    MPM.add(createCorrelatedValuePropagationPass());
-    MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
-    MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
-  }
+  MPM.add(createJumpThreadingPass());         // Thread jumps
+  MPM.add(createCorrelatedValuePropagationPass());
+  MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
+  MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
 
   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
 
   if (RerollLoops)
     MPM.add(createLoopRerollPass());
 
-  // TODO: Investigate if this is too expensive at O1.
   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
   MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
   // Clean up after everything.
@@ -912,8 +899,7 @@ void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
 
   // LTO provides additional opportunities for tailcall elimination due to
   // link-time inlining, and visibility of nocapture attribute.
-  if (OptLevel > 1)
-    PM.add(createTailCallEliminationPass());
+  PM.add(createTailCallEliminationPass());
 
   // Infer attributes on declarations, call sites, arguments, etc.
   PM.add(createPostOrderFunctionAttrsLegacyPass()); // Add nocapture.