Schedule Hot Cold Splitting pass after most optimization passes

Summary:
In the new+old pass manager, hot cold splitting was schedule too early.
Thanks to Vedant for pointing this out.

Reviewers: sebpop, vsk

Reviewed By: sebpop, vsk

Subscribers: mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D53437

llvm-svn: 344869

llvm/lib/Passes/PassBuilder.cpp

@@ -621,9 +621,6 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
                                            true));
   }
 
-  if (EnableHotColdSplit)
-    MPM.addPass(HotColdSplittingPass());
-
   // Interprocedural constant propagation now that basic cleanup has occurred
   // and prior to optimizing globals.
   // FIXME: This position in the pipeline hasn't been carefully considered in
@@ -713,6 +710,9 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
   MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
       buildFunctionSimplificationPipeline(Level, Phase, DebugLogging)));
 
+  if (EnableHotColdSplit)
+    MPM.addPass(HotColdSplittingPass());
+
   for (auto &C : CGSCCOptimizerLateEPCallbacks)
     C(MainCGPipeline, Level);
 

llvm/lib/Transforms/IPO/PassManagerBuilder.cpp

@@ -499,9 +499,6 @@ void PassManagerBuilder::populateModulePassManager(
   // Infer attributes about declarations if possible.
   MPM.add(createInferFunctionAttrsLegacyPass());
 
-  if (EnableHotColdSplit)
-    MPM.add(createHotColdSplittingPass());
-
   addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
 
   if (OptLevel > 2)
@@ -735,6 +732,9 @@ void PassManagerBuilder::populateModulePassManager(
   // flattening of blocks.
   MPM.add(createDivRemPairsPass());
 
+  if (EnableHotColdSplit)
+    MPM.add(createHotColdSplittingPass());
+
   // LoopSink (and other loop passes since the last simplifyCFG) might have
   // resulted in single-entry-single-exit or empty blocks. Clean up the CFG.
   MPM.add(createCFGSimplificationPass());

llvm/test/Other/opt-hot-cold-split.ll

@@ -0,0 +1,292 @@
+; RUN: opt -mtriple=x86_64-- -Os -hotcoldsplit -debug-pass=Structure < %s -o /dev/null 2>&1 | FileCheck %s
+; REQUIRES: asserts
+
+; CHECK-LABEL: Pass Arguments:
+; CHECK-NEXT: Target Transform Information
+; CHECK-NEXT: Type-Based Alias Analysis
+; CHECK-NEXT: Scoped NoAlias Alias Analysis
+; CHECK-NEXT: Assumption Cache Tracker
+; CHECK-NEXT: Target Library Information
+; CHECK-NEXT:   FunctionPass Manager
+; CHECK-NEXT:     Module Verifier
+; CHECK-NEXT:     Instrument function entry/exit with calls to e.g. mcount() (pre inlining)
+; CHECK-NEXT:     Simplify the CFG
+; CHECK-NEXT:     Dominator Tree Construction
+; CHECK-NEXT:     SROA
+; CHECK-NEXT:     Early CSE
+; CHECK-NEXT:     Lower 'expect' Intrinsics
+; CHECK-NEXT:  Pass Arguments:
+; CHECK-NEXT:  Target Library Information
+; CHECK-NEXT:  Target Transform Information
+; CHECK-NEXT:  Target Pass Configuration
+; CHECK-NEXT:  Type-Based Alias Analysis
+; CHECK-NEXT:  Scoped NoAlias Alias Analysis
+; CHECK-NEXT:  Assumption Cache Tracker
+; CHECK-NEXT:  Profile summary info
+; CHECK-NEXT:    ModulePass Manager
+; CHECK-NEXT:      Force set function attributes
+; CHECK-NEXT:      Infer set function attributes
+; CHECK-NEXT:      Interprocedural Sparse Conditional Constant Propagation
+; CHECK-NEXT:        Unnamed pass: implement Pass::getPassName()
+; CHECK-NEXT:     Called Value Propagation
+; CHECK-NEXT:     Global Variable Optimizer
+; CHECK-NEXT:       Unnamed pass: implement Pass::getPassName()
+; CHECK-NEXT:     FunctionPass Manager
+; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Promote Memory to Register
+; CHECK-NEXT:     Dead Argument Elimination
+; CHECK-NEXT:     FunctionPass Manager
+; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Natural Loop Information
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Simplify the CFG
+; CHECK-NEXT:     CallGraph Construction
+; CHECK-NEXT:     Globals Alias Analysis
+; CHECK-NEXT:     Call Graph SCC Pass Manager
+; CHECK-NEXT:       Remove unused exception handling info
+; CHECK-NEXT:       Function Integration/Inlining
+; CHECK-NEXT:       Deduce function attributes
+; CHECK-NEXT:       FunctionPass Manager
+; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         SROA
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
+; CHECK-NEXT:         Early CSE w/ MemorySSA
+; CHECK-NEXT:         Speculatively execute instructions if target has divergent branches
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Lazy Value Information Analysis
+; CHECK-NEXT:         Jump Threading
+; CHECK-NEXT:         Value Propagation
+; CHECK-NEXT:         Simplify the CFG
+; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Natural Loop Information
+; CHECK-NEXT:         Lazy Branch Probability Analysis
+; CHECK-NEXT:         Lazy Block Frequency Analysis
+; CHECK-NEXT:         Optimization Remark Emitter
+; CHECK-NEXT:         Combine redundant instructions
+; CHECK-NEXT:         Optimization Remark Emitter
+; CHECK-NEXT:         Tail Call Elimination
+; CHECK-NEXT:         Simplify the CFG
+; CHECK-NEXT:         Reassociate expressions
+; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Natural Loop Information
+; CHECK-NEXT:         Canonicalize natural loops
+; CHECK-NEXT:         LCSSA Verifier
+; CHECK-NEXT:         Loop-Closed SSA Form Pass
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Scalar Evolution Analysis
+; CHECK-NEXT:         Loop Pass Manager
+; CHECK-NEXT:           Rotate Loops
+; CHECK-NEXT:           Loop Invariant Code Motion
+; CHECK-NEXT:           Unswitch loops
+; CHECK-NEXT:         Simplify the CFG
+; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Natural Loop Information
+; CHECK-NEXT:         Lazy Branch Probability Analysis
+; CHECK-NEXT:         Lazy Block Frequency Analysis
+; CHECK-NEXT:         Optimization Remark Emitter
+; CHECK-NEXT:         Combine redundant instructions
+; CHECK-NEXT:         Canonicalize natural loops
+; CHECK-NEXT:         LCSSA Verifier
+; CHECK-NEXT:         Loop-Closed SSA Form Pass
+; CHECK-NEXT:         Scalar Evolution Analysis
+; CHECK-NEXT:         Loop Pass Manager
+; CHECK-NEXT:           Induction Variable Simplification
+; CHECK-NEXT:           Recognize loop idioms
+; CHECK-NEXT:           Delete dead loops
+; CHECK-NEXT:           Unroll loops
+; CHECK-NEXT:         MergedLoadStoreMotion
+; CHECK-NEXT:         Phi Values Analysis
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory Dependence Analysis
+; CHECK-NEXT:         Lazy Branch Probability Analysis
+; CHECK-NEXT:         Lazy Block Frequency Analysis
+; CHECK-NEXT:         Optimization Remark Emitter
+; CHECK-NEXT:         Global Value Numbering
+; CHECK-NEXT:         Phi Values Analysis
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory Dependence Analysis
+; CHECK-NEXT:         MemCpy Optimization
+; CHECK-NEXT:         Sparse Conditional Constant Propagation
+; CHECK-NEXT:         Demanded bits analysis
+; CHECK-NEXT:         Bit-Tracking Dead Code Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Natural Loop Information
+; CHECK-NEXT:         Lazy Branch Probability Analysis
+; CHECK-NEXT:         Lazy Block Frequency Analysis
+; CHECK-NEXT:         Optimization Remark Emitter
+; CHECK-NEXT:         Combine redundant instructions
+; CHECK-NEXT:         Lazy Value Information Analysis
+; CHECK-NEXT:         Jump Threading
+; CHECK-NEXT:         Value Propagation
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Phi Values Analysis
+; CHECK-NEXT:         Memory Dependence Analysis
+; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Natural Loop Information
+; CHECK-NEXT:         Canonicalize natural loops
+; CHECK-NEXT:         LCSSA Verifier
+; CHECK-NEXT:         Loop-Closed SSA Form Pass
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Scalar Evolution Analysis
+; CHECK-NEXT:         Loop Pass Manager
+; CHECK-NEXT:           Loop Invariant Code Motion
+; CHECK-NEXT:         Post-Dominator Tree Construction
+; CHECK-NEXT:         Aggressive Dead Code Elimination
+; CHECK-NEXT:         Simplify the CFG
+; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Natural Loop Information
+; CHECK-NEXT:         Lazy Branch Probability Analysis
+; CHECK-NEXT:         Lazy Block Frequency Analysis
+; CHECK-NEXT:         Optimization Remark Emitter
+; CHECK-NEXT:         Combine redundant instructions
+; CHECK-NEXT:     A No-Op Barrier Pass
+; CHECK-NEXT:     Eliminate Available Externally Globals
+; CHECK-NEXT:     CallGraph Construction
+; CHECK-NEXT:     Deduce function attributes in RPO
+; CHECK-NEXT:     Global Variable Optimizer
+; CHECK-NEXT:       Unnamed pass: implement Pass::getPassName()
+; CHECK-NEXT:     Dead Global Elimination
+; CHECK-NEXT:     CallGraph Construction
+; CHECK-NEXT:     Globals Alias Analysis
+; CHECK-NEXT:     FunctionPass Manager
+; CHECK-NEXT:       Float to int
+; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Natural Loop Information
+; CHECK-NEXT:       Canonicalize natural loops
+; CHECK-NEXT:       LCSSA Verifier
+; CHECK-NEXT:       Loop-Closed SSA Form Pass
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Loop Pass Manager
+; CHECK-NEXT:         Rotate Loops
+; CHECK-NEXT:       Loop Access Analysis
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Loop Distribution
+; CHECK-NEXT:       Branch Probability Analysis
+; CHECK-NEXT:       Block Frequency Analysis
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Loop Access Analysis
+; CHECK-NEXT:       Demanded bits analysis
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Loop Vectorization
+; CHECK-NEXT:       Canonicalize natural loops
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Loop Access Analysis
+; CHECK-NEXT:       Loop Load Elimination
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Simplify the CFG
+; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Natural Loop Information
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Demanded bits analysis
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       SLP Vectorizer
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Canonicalize natural loops
+; CHECK-NEXT:       LCSSA Verifier
+; CHECK-NEXT:       Loop-Closed SSA Form Pass
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Loop Pass Manager
+; CHECK-NEXT:         Unroll loops
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Canonicalize natural loops
+; CHECK-NEXT:       LCSSA Verifier
+; CHECK-NEXT:       Loop-Closed SSA Form Pass
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Loop Pass Manager
+; CHECK-NEXT:         Loop Invariant Code Motion
+; CHECK-NEXT:       Alignment from assumptions
+; CHECK-NEXT:     Strip Unused Function Prototypes
+; CHECK-NEXT:     Dead Global Elimination
+; CHECK-NEXT:     Merge Duplicate Global Constants
+; CHECK-NEXT:     FunctionPass Manager
+; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Natural Loop Information
+; CHECK-NEXT:       Branch Probability Analysis
+; CHECK-NEXT:       Block Frequency Analysis
+; CHECK-NEXT:       Canonicalize natural loops
+; CHECK-NEXT:       LCSSA Verifier
+; CHECK-NEXT:       Loop-Closed SSA Form Pass
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Scalar Evolution Analysis
+; CHECK-NEXT:       Branch Probability Analysis
+; CHECK-NEXT:       Block Frequency Analysis
+; CHECK-NEXT:       Loop Pass Manager
+; CHECK-NEXT:         Loop Sink
+; CHECK-NEXT:       Lazy Branch Probability Analysis
+; CHECK-NEXT:       Lazy Block Frequency Analysis
+; CHECK-NEXT:       Optimization Remark Emitter
+; CHECK-NEXT:       Remove redundant instructions
+; CHECK-NEXT:       Hoist/decompose integer division and remainder
+; CHECK-NEXT:       Simplify the CFG
+; CHECK-NEXT:     Hot Cold Splitting
+; CHECK-NEXT:       Unnamed pass: implement Pass::getPassName()
+; CHECK-NEXT:     FunctionPass Manager
+; CHECK-NEXT:       Module Verifier
+; CHECK-NEXT:     Bitcode Writer
+; CHECK-NEXT: Pass Arguments:  -domtree
+; CHECK-NEXT:   FunctionPass Manager
+; CHECK-NEXT:     Dominator Tree Construction
+; CHECK-NEXT: Pass Arguments:  -targetlibinfo -domtree -loops -branch-prob -block-freq
+; CHECK-NEXT: Target Library Information
+; CHECK-NEXT:   FunctionPass Manager
+; CHECK-NEXT:     Dominator Tree Construction
+; CHECK-NEXT:     Natural Loop Information
+; CHECK-NEXT:     Branch Probability Analysis
+; CHECK-NEXT:     Block Frequency Analysis
+; CHECK-NEXT: Pass Arguments:  -targetlibinfo -domtree -loops -branch-prob -block-freq
+; CHECK-NEXT: Target Library Information
+; CHECK-NEXT:   FunctionPass Manager
+; CHECK-NEXT:     Dominator Tree Construction
+; CHECK-NEXT:     Natural Loop Information
+; CHECK-NEXT:     Branch Probability Analysis
+; CHECK-NEXT:     Block Frequency Analysis
+; CHECK-NEXT: Pass Arguments:  -targetlibinfo -domtree -loops -branch-prob -block-freq
+; CHECK-NEXT: Target Library Information
+; CHECK-NEXT:   FunctionPass Manager
+; CHECK-NEXT:     Dominator Tree Construction
+; CHECK-NEXT:     Natural Loop Information
+; CHECK-NEXT:     Branch Probability Analysis
+; CHECK-NEXT:     Block Frequency Analysis