Revert "As a follow-up to my initial mail to llvm-dev here's a first pass at the O1 described there."

This reverts commit 8ff85ed905a7306977d07a5cd67ab4d5a56fafb4.

This commit introduced 9 new failures on lldb buildbot host at http://lab.llvm.org:8014/builders/lldb-aarch64-ubuntu

Following tests were failing:
    lldb-api :: functionalities/tail_call_frames/ambiguous_tail_call_seq1/TestAmbiguousTailCallSeq1.py
    lldb-api :: functionalities/tail_call_frames/ambiguous_tail_call_seq2/TestAmbiguousTailCallSeq2.py
    lldb-api :: functionalities/tail_call_frames/disambiguate_call_site/TestDisambiguateCallSite.py
    lldb-api :: functionalities/tail_call_frames/disambiguate_paths_to_common_sink/TestDisambiguatePathsToCommonSink.py
    lldb-api :: functionalities/tail_call_frames/disambiguate_tail_call_seq/TestDisambiguateTailCallSeq.py
    lldb-api :: functionalities/tail_call_frames/inlining_and_tail_calls/TestInliningAndTailCalls.py
    lldb-api :: functionalities/tail_call_frames/sbapi_support/TestTailCallFrameSBAPI.py
    lldb-api :: functionalities/tail_call_frames/thread_step_out_message/TestArtificialFrameStepOutMessage.py
    lldb-api :: functionalities/tail_call_frames/thread_step_out_or_return/TestSteppingOutWithArtificialFrames.py
    lldb-api :: functionalities/tail_call_frames/unambiguous_sequence/TestUnambiguousTailCalls.py

Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65410

1 files changed, 16 insertions, 30 deletions

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.