[ICP] Migrate to OptimizationRemarkEmitter

[anemet]

Summary

This is a module pass so for the old PM, we can't use ORE, the function
analysis pass. Instead ORE is created on the fly.

A few notes:

• isPromotionLegal is folded in the caller since we want to emit the Function

in the remark but we can only do that if the symbol table look-up succeeded.

• There was good test coverage for remarks in this pass.

• promoteIndirectCall uses ORE conditionally since it's also used from

SampleProfile which does not use ORE yet.

Fixes PR33792.

[davide]

LGTM, thanks for taking care of this one

llvm/trunk/include/llvm/Transforms/Instrumentation.h

inline void *getDFSanRetValTLSPtrForJIT() {
   return (void *)&__dfsan_retval_tls;
 }
 #endif
 
 namespace llvm {
 
 class FunctionPass;
 class ModulePass;
+class OptimizationRemarkEmitter;
 
 /// Instrumentation passes often insert conditional checks into entry blocks.
 /// Call this function before splitting the entry block to move instructions
 /// that must remain in the entry block up before the split point. Static
 /// allocas and llvm.localescape calls, for example, must remain in the entry
 /// block.
 BasicBlock::iterator PrepareToSplitEntryBlock(BasicBlock &BB,
                                               BasicBlock::iterator IP);

 // TotalCount is the profile count value that the instruction executes.
 // Count is the profile count value that F is the target function.
 // These two values are used to update the branch weight.
 // If \p AttachProfToDirectCall is true, a prof metadata is attached to the
 // new direct call to contain \p Count.
 // Returns the promoted direct call instruction.
 Instruction *promoteIndirectCall(Instruction *Inst, Function *F, uint64_t Count,
                                  uint64_t TotalCount,
-                                 bool AttachProfToDirectCall);
+                                 bool AttachProfToDirectCall,
+                                 OptimizationRemarkEmitter *ORE = nullptr);
 
 /// Options for the frontend instrumentation based profiling pass.
 struct InstrProfOptions {
   // Add the 'noredzone' attribute to added runtime library calls.
   bool NoRedZone = false;
 
   // Do counter register promotion
   bool DoCounterPromotion = false;

llvm/trunk/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp

 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Analysis/BlockFrequencyInfo.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
 #include "llvm/Analysis/IndirectCallSiteVisitor.h"
+#include "llvm/Analysis/OptimizationDiagnosticInfo.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/Instruction.h"
private:
   Module *M;
 
   // Symtab that maps indirect call profile values to function names and
   // defines.
   InstrProfSymtab *Symtab;
 
   bool SamplePGO;
 
-  // Test if we can legally promote this direct-call of Target.
-  bool isPromotionLegal(Instruction *Inst, uint64_t Target, Function *&F,
-                        const char **Reason = nullptr);
+  OptimizationRemarkEmitter &ORE;
 
   // A struct that records the direct target and it's call count.
   struct PromotionCandidate {
     Function *TargetFunction;
     uint64_t Count;
     PromotionCandidate(Function *F, uint64_t C) : TargetFunction(F), Count(C) {}
   };
 
uint32_t tryToPromote(Instruction *Inst,
                         uint64_t &TotalCount);
 
   // Noncopyable
   ICallPromotionFunc(const ICallPromotionFunc &other) = delete;
   ICallPromotionFunc &operator=(const ICallPromotionFunc &other) = delete;
 
 public:
   ICallPromotionFunc(Function &Func, Module *Modu, InstrProfSymtab *Symtab,
-                     bool SamplePGO)
-      : F(Func), M(Modu), Symtab(Symtab), SamplePGO(SamplePGO) {}
+                     bool SamplePGO, OptimizationRemarkEmitter &ORE)
+      : F(Func), M(Modu), Symtab(Symtab), SamplePGO(SamplePGO), ORE(ORE) {}
 
   bool processFunction();
 };
 } // end anonymous namespace
 
 bool llvm::isLegalToPromote(Instruction *Inst, Function *F,
                             const char **Reason) {
   // Check the return type.
for (unsigned I = 0; I < ParamNum; ++I) {
     }
   }
 
   DEBUG(dbgs() << " #" << NumOfPGOICallPromotion << " Promote the icall to "
                << F->getName() << "\n");
   return true;
 }
 
-bool ICallPromotionFunc::isPromotionLegal(Instruction *Inst, uint64_t Target,
-                                          Function *&TargetFunction,
-                                          const char **Reason) {
-  TargetFunction = Symtab->getFunction(Target);
-  if (TargetFunction == nullptr) {
-    *Reason = "Cannot find the target";
-    return false;
-  }
-  return isLegalToPromote(Inst, TargetFunction, Reason);
-}
-
 // Indirect-call promotion heuristic. The direct targets are sorted based on
 // the count. Stop at the first target that is not promoted.
 std::vector<ICallPromotionFunc::PromotionCandidate>
 ICallPromotionFunc::getPromotionCandidatesForCallSite(
     Instruction *Inst, const ArrayRef<InstrProfValueData> &ValueDataRef,
     uint64_t TotalCount, uint32_t NumCandidates) {
   std::vector<PromotionCandidate> Ret;
 
for (uint32_t I = 0; I < NumCandidates; I++) {
     uint64_t Count = ValueDataRef[I].Count;
     assert(Count <= TotalCount);
     uint64_t Target = ValueDataRef[I].Value;
     DEBUG(dbgs() << " Candidate " << I << " Count=" << Count
                  << "  Target_func: " << Target << "\n");
 
     if (ICPInvokeOnly && dyn_cast<CallInst>(Inst)) {
       DEBUG(dbgs() << " Not promote: User options.\n");
+      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UserOptions", Inst)
+               << " Not promote: User options");
       break;
     }
     if (ICPCallOnly && dyn_cast<InvokeInst>(Inst)) {
       DEBUG(dbgs() << " Not promote: User option.\n");
+      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UserOptions", Inst)
+               << " Not promote: User options");
       break;
     }
     if (ICPCutOff != 0 && NumOfPGOICallPromotion >= ICPCutOff) {
       DEBUG(dbgs() << " Not promote: Cutoff reached.\n");
+      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "CutOffReached", Inst)
+               << " Not promote: Cutoff reached");
+      break;
+    }
+
+    Function *TargetFunction = Symtab->getFunction(Target);
+    if (TargetFunction == nullptr) {
+      DEBUG(dbgs() << " Not promote: Cannot find the target\n");
+      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UnableToFindTarget", Inst)
+               << "Cannot promote indirect call: target not found");
       break;
     }
-    Function *TargetFunction = nullptr;
+
     const char *Reason = nullptr;
-    if (!isPromotionLegal(Inst, Target, TargetFunction, &Reason)) {
-      StringRef TargetFuncName = Symtab->getFuncName(Target);
-      DEBUG(dbgs() << " Not promote: " << Reason << "\n");
-      emitOptimizationRemarkMissed(
-          F.getContext(), "pgo-icall-prom", F, Inst->getDebugLoc(),
-          Twine("Cannot promote indirect call to ") +
-              (TargetFuncName.empty() ? Twine(Target) : Twine(TargetFuncName)) +
-              Twine(" with count of ") + Twine(Count) + ": " + Reason);
+    if (!isLegalToPromote(Inst, TargetFunction, &Reason)) {
+      using namespace ore;
+      ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "UnableToPromote", Inst)
+               << "Cannot promote indirect call to "
+               << NV("TargetFunction", TargetFunction) << " with count of "
+               << NV("Count", Count) << ": " << Reason);
       break;
     }
+
     Ret.push_back(PromotionCandidate(TargetFunction, Count));
     TotalCount -= Count;
   }
   return Ret;
 }
 
 // Create a diamond structure for If_Then_Else. Also update the profile
 // count. Do the fix-up for the invoke instruction.

 // value. Branch weights metadata also updated.
 // If \p AttachProfToDirectCall is true, a prof metadata is attached to the
 // new direct call to contain \p Count. This is used by SamplePGO inliner to
 // check callsite hotness.
 // Returns the promoted direct call instruction.
 Instruction *llvm::promoteIndirectCall(Instruction *Inst,
                                        Function *DirectCallee, uint64_t Count,
                                        uint64_t TotalCount,
-                                       bool AttachProfToDirectCall) {
+                                       bool AttachProfToDirectCall,
+                                       OptimizationRemarkEmitter *ORE) {
   assert(DirectCallee != nullptr);
   BasicBlock *BB = Inst->getParent();
   // Just to suppress the non-debug build warning.
   (void)BB;
   DEBUG(dbgs() << "\n\n== Basic Block Before ==\n");
   DEBUG(dbgs() << *BB << "\n");
 
   BasicBlock *DirectCallBB, *IndirectCallBB, *MergeBB;
fixupPHINodeForNormalDest(Inst, II->getNormalDest(), MergeBB,
                               IndirectCallBB, NewInst);
   }
 
   insertCallRetPHI(Inst, NewInst, DirectCallee);
 
   DEBUG(dbgs() << "\n== Basic Blocks After ==\n");
   DEBUG(dbgs() << *BB << *DirectCallBB << *IndirectCallBB << *MergeBB << "\n");
 
-  emitOptimizationRemark(
-      BB->getContext(), "pgo-icall-prom", *BB->getParent(), Inst->getDebugLoc(),
-      Twine("Promote indirect call to ") + DirectCallee->getName() +
-          " with count " + Twine(Count) + " out of " + Twine(TotalCount));
+  using namespace ore;
+  if (ORE)
+    ORE->emit(OptimizationRemark(DEBUG_TYPE, "Promoted", Inst)
+              << "Promote indirect call to " << NV("DirectCallee", DirectCallee)
+              << " with count " << NV("Count", Count) << " out of "
+              << NV("TotalCount", TotalCount));
   return NewInst;
 }
 
 // Promote indirect-call to conditional direct-call for one callsite.
 uint32_t ICallPromotionFunc::tryToPromote(
     Instruction *Inst, const std::vector<PromotionCandidate> &Candidates,
     uint64_t &TotalCount) {
   uint32_t NumPromoted = 0;
 
   for (auto &C : Candidates) {
     uint64_t Count = C.Count;
-    promoteIndirectCall(Inst, C.TargetFunction, Count, TotalCount, SamplePGO);
+    promoteIndirectCall(Inst, C.TargetFunction, Count, TotalCount, SamplePGO,
+                        &ORE);
     assert(TotalCount >= Count);
     TotalCount -= Count;
     NumOfPGOICallPromotion++;
     NumPromoted++;
   }
   return NumPromoted;
 }
 
for (auto &I : findIndirectCallSites(F)) {
     // Otherwise we need update with the un-promoted records back.
     annotateValueSite(*M, *I, ICallProfDataRef.slice(NumPromoted), TotalCount,
                       IPVK_IndirectCallTarget, NumCandidates);
   }
   return Changed;
 }
 
 // A wrapper function that does the actual work.
-static bool promoteIndirectCalls(Module &M, bool InLTO, bool SamplePGO) {
+static bool promoteIndirectCalls(Module &M, bool InLTO, bool SamplePGO,
+                                 ModuleAnalysisManager *AM = nullptr) {
   if (DisableICP)
     return false;
   InstrProfSymtab Symtab;
   if (Error E = Symtab.create(M, InLTO)) {
     std::string SymtabFailure = toString(std::move(E));
     DEBUG(dbgs() << "Failed to create symtab: " << SymtabFailure << "\n");
     (void)SymtabFailure;
     return false;
   }
   bool Changed = false;
   for (auto &F : M) {
     if (F.isDeclaration())
       continue;
     if (F.hasFnAttribute(Attribute::OptimizeNone))
       continue;
-    ICallPromotionFunc ICallPromotion(F, &M, &Symtab, SamplePGO);
+
+    std::unique_ptr<OptimizationRemarkEmitter> OwnedORE;
+    OptimizationRemarkEmitter *ORE;
+    if (AM) {
+      auto &FAM =
+          AM->getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
+      ORE = &FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
+    } else {
+      OwnedORE = make_unique<OptimizationRemarkEmitter>(&F);
+      ORE = OwnedORE.get();
+    }
+
+    ICallPromotionFunc ICallPromotion(F, &M, &Symtab, SamplePGO, *ORE);
     bool FuncChanged = ICallPromotion.processFunction();
     if (ICPDUMPAFTER && FuncChanged) {
       DEBUG(dbgs() << "\n== IR Dump After =="; F.print(dbgs()));
       DEBUG(dbgs() << "\n");
     }
     Changed |= FuncChanged;
     if (ICPCutOff != 0 && NumOfPGOICallPromotion >= ICPCutOff) {
       DEBUG(dbgs() << " Stop: Cutoff reached.\n");
       break;
     }
   }
   return Changed;
 }
 
 bool PGOIndirectCallPromotionLegacyPass::runOnModule(Module &M) {
   // Command-line option has the priority for InLTO.
   return promoteIndirectCalls(M, InLTO | ICPLTOMode,
                               SamplePGO | ICPSamplePGOMode);
 }
 
 PreservedAnalyses PGOIndirectCallPromotion::run(Module &M,
                                                 ModuleAnalysisManager &AM) {
-  if (!promoteIndirectCalls(M, InLTO | ICPLTOMode,
-                            SamplePGO | ICPSamplePGOMode))
+  if (!promoteIndirectCalls(M, InLTO | ICPLTOMode, SamplePGO | ICPSamplePGOMode,
+                            &AM))
     return PreservedAnalyses::all();
 
   return PreservedAnalyses::none();
 }

llvm/trunk/test/Other/new-pm-lto-defaults.ll

 ; Basic test for the new LTO pipeline.
 ; For now the only difference is between -O1 and everything else, so
 ; -O2, -O3, -Os, -Oz are the same.
 
 ; RUN: opt -disable-verify -debug-pass-manager \
 ; RUN:     -passes='lto<O1>' -S %s 2>&1 \
-; RUN:     | FileCheck %s --check-prefix=CHECK-O
+; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O1
 ; RUN: opt -disable-verify -debug-pass-manager \
 ; RUN:     -passes='lto<O2>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O2
 ; RUN: opt -disable-verify -debug-pass-manager \
 ; RUN:     -passes='lto<O3>' -S  %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O2
 ; RUN: opt -disable-verify -debug-pass-manager \
 ; RUN:     -passes='lto<Os>' -S %s 2>&1 \

 ; CHECK-O: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O2-NEXT: PGOIndirectCallPromotion
+; CHECK-O2-NEXT: Running analysis: InnerAnalysisManagerProxy<FunctionAnalysisManager
+; CHECK-O2-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O2-NEXT: Running pass: IPSCCPPass
 ; CHECK-O-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor<{{.*}}PostOrderFunctionAttrsPass>
-; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
-; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
+; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy<CGSCCAnalysisManager
+; CHECK-O1-NEXT: Running analysis: InnerAnalysisManagerProxy<FunctionAnalysisManager
 ; CHECK-O-NEXT: Running analysis: LazyCallGraphAnalysis
 ; CHECK-O-NEXT: Running analysis: FunctionAnalysisManagerCGSCCProxy
 ; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy<{{.*}}LazyCallGraph{{.*}}>
 ; CHECK-O-NEXT: Running analysis: AAManager
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: ReversePostOrderFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: CallGraphAnalysis
 ; CHECK-O-NEXT: Running pass: GlobalSplitPass
 ; CHECK-O-NEXT: Running pass: WholeProgramDevirtPass
 ; CHECK-O2-NEXT: Running pass: GlobalOptPass
 ; CHECK-O2-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PromotePass>
 ; CHECK-O2-NEXT: Running analysis: DominatorTreeAnalysis
 ; CHECK-O2-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O2-NEXT: Running pass: ConstantMergePass
 ; CHECK-O2-NEXT: Running pass: DeadArgumentEliminationPass
 ; CHECK-O2-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
 ; CHECK-O2-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O2-NEXT: Running pass: InstCombinePass
-; CHECK-O2-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-EP-Peephole-NEXT: Running pass: NoOpFunctionPass
 ; CHECK-O2-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O2-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor<{{.*}}InlinerPass>
 ; CHECK-O2-NEXT: Running pass: GlobalOptPass
 ; CHECK-O2-NEXT: Running pass: GlobalDCEPass
 ; CHECK-O2-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
 ; CHECK-O2-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O2-NEXT: Running pass: InstCombinePass

llvm/trunk/test/Other/new-pm-thinlto-defaults.ll

 ; RUN:     -passes='thinlto<Oz>' -S %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefixes=CHECK-O,CHECK-Oz,CHECK-POSTLINK-O,CHECK-POSTLINK-Oz
 ;
 ; CHECK-O: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
 ; CHECK-POSTLINK-O-NEXT: Running pass: PGOIndirectCallPromotion
+; CHECK-POSTLINK-O-NEXT: Running analysis: InnerAnalysisManagerProxy<FunctionAnalysisManager
+; CHECK-POSTLINK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
-; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
+; CHECK-PRELINK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-O-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O-NEXT: Running pass: SROA
 ; CHECK-O-NEXT: Running analysis: DominatorTreeAnalysis
 ; CHECK-O-NEXT: Running pass: EarlyCSEPass
 ; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: IPSCCPPass
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PromotePass>
 ; CHECK-O-NEXT: Running pass: DeadArgumentEliminationPass
 ; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: InstCombinePass
-; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
+; CHECK-PRELINK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}GlobalsAA
 ; CHECK-O-NEXT: Running analysis: GlobalsAA
 ; CHECK-O-NEXT: Running analysis: CallGraphAnalysis
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}ProfileSummaryAnalysis
 ; CHECK-O-NEXT: Running analysis: ProfileSummaryAnalysis
 ; CHECK-O-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor<{{.*}}LazyCallGraph{{.*}}>

llvm/trunk/test/Transforms/PGOProfile/icp_mismatch_msg.ll

 ; RUN: opt < %s -pgo-icall-prom -pass-remarks-missed=pgo-icall-prom -S 2>& 1 | FileCheck %s
 ; RUN: opt < %s -passes=pgo-icall-prom -pass-remarks-missed=pgo-icall-prom -S 2>& 1 | FileCheck %s
 
 ; CHECK: remark: <unknown>:0:0: Cannot promote indirect call to func4 with count of 1234: The number of arguments mismatch
-; CHECK: remark: <unknown>:0:0: Cannot promote indirect call to 11517462787082255043 with count of 2345: Cannot find the target
+; CHECK: remark: <unknown>:0:0: Cannot promote indirect call: target not found
 ; CHECK: remark: <unknown>:0:0: Cannot promote indirect call to func2 with count of 7890: Return type mismatch
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @foo = common global i32 ()* null, align 8
 @foo2 = common global i32 ()* null, align 8
 @foo3 = common global i32 ()* null, align 8