[CodeGen] Don't require AA in SDAG/2Addr at CodeGenOpt::None.

[ab]

Summary

This is an alternative to D31642.

Before r247167, the pass manager builder controlled which AA
implementations were used, exporting them all in the AliasAnalysis
analysis group.

Now, AAResultsWrapperPass always uses BasicAA, but still uses other
AA implementations if made available in the pass pipeline.

But regardless, both SDAG and TwoAddress are required at O0, and really
don't need to be doing fancy optimizations based on useful AA results.

Don't require AA at CodeGenOpt::None, and only use it otherwise.

This does have a functional impact (and one testcase is pessimized
because we can't reuse a load).
But I think that's desirable no matter what.

[chandlerc]

LGTM, nice!

llvm/trunk/include/llvm/CodeGen/SelectionDAG.h

if (N.getNode())
       checkForCycles(this);
     return Root;
   }
 
   /// This iterates over the nodes in the SelectionDAG, folding
   /// certain types of nodes together, or eliminating superfluous nodes.  The
   /// Level argument controls whether Combine is allowed to produce nodes and
   /// types that are illegal on the target.
-  void Combine(CombineLevel Level, AliasAnalysis &AA,
+  void Combine(CombineLevel Level, AliasAnalysis *AA,
                CodeGenOpt::Level OptLevel);
 
   /// This transforms the SelectionDAG into a SelectionDAG that
   /// only uses types natively supported by the target.
   /// Returns "true" if it made any changes.
   ///
   /// Note that this is an involved process that may invalidate pointers into
   /// the graph.

llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

class DAGCombiner {
 
     /// \brief Set of nodes which have been combined (at least once).
     ///
     /// This is used to allow us to reliably add any operands of a DAG node
     /// which have not yet been combined to the worklist.
     SmallPtrSet<SDNode *, 32> CombinedNodes;
 
     // AA - Used for DAG load/store alias analysis.
-    AliasAnalysis &AA;
+    AliasAnalysis *AA;
 
     /// When an instruction is simplified, add all users of the instruction to
     /// the work lists because they might get more simplified now.
     void AddUsersToWorklist(SDNode *N) {
       for (SDNode *Node : N->uses())
         AddToWorklist(Node);
     }
 
private:
     ///     (trunc (and X, C)) -> (and (trunc X), (trunc C))
     ///
     /// \p N needs to be a truncation and its first operand an AND. Other
     /// requirements are checked by the function (e.g. that trunc is
     /// single-use) and if missed an empty SDValue is returned.
     SDValue distributeTruncateThroughAnd(SDNode *N);
 
   public:
-    DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL)
+    DAGCombiner(SelectionDAG &D, AliasAnalysis *AA, CodeGenOpt::Level OL)
         : DAG(D), TLI(D.getTargetLoweringInfo()), Level(BeforeLegalizeTypes),
-          OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(A) {
+          OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(AA) {
       ForCodeSize = DAG.getMachineFunction().getFunction()->optForSize();
 
       MaximumLegalStoreInBits = 0;
       for (MVT VT : MVT::all_valuetypes())
         if (EVT(VT).isSimple() && VT != MVT::Other &&
             TLI.isTypeLegal(EVT(VT)) &&
             VT.getSizeInBits() >= MaximumLegalStoreInBits)
           MaximumLegalStoreInBits = VT.getSizeInBits();
bool UseAA = CombinerGlobalAA.getNumOccurrences() > 0
                    ? CombinerGlobalAA
                    : DAG.getSubtarget().useAA();
 #ifndef NDEBUG
   if (CombinerAAOnlyFunc.getNumOccurrences() &&
       CombinerAAOnlyFunc != DAG.getMachineFunction().getName())
     UseAA = false;
 #endif
 
-  if (UseAA &&
+  if (UseAA && AA &&
       Op0->getMemOperand()->getValue() && Op1->getMemOperand()->getValue()) {
     // Use alias analysis information.
     int64_t MinOffset = std::min(SrcValOffset0, SrcValOffset1);
     int64_t Overlap0 = NumBytes0 + SrcValOffset0 - MinOffset;
     int64_t Overlap1 = NumBytes1 + SrcValOffset1 - MinOffset;
     AliasResult AAResult =
-        AA.alias(MemoryLocation(Op0->getMemOperand()->getValue(), Overlap0,
+        AA->alias(MemoryLocation(Op0->getMemOperand()->getValue(), Overlap0,
                                  UseTBAA ? Op0->getAAInfo() : AAMDNodes()),
                   MemoryLocation(Op1->getMemOperand()->getValue(), Overlap1,
-                                UseTBAA ? Op1->getAAInfo() : AAMDNodes()));
+                                 UseTBAA ? Op1->getAAInfo() : AAMDNodes()) );
     if (AAResult == NoAlias)
       return false;
   }
 
   // Otherwise we have to assume they alias.
   return true;
 }
 
bool DAGCombiner::findBetterNeighborChains(StoreSDNode *St) {
   // the chains more complicated by introducing new TokenFactors.
   for (auto Replacement : BetterChains)
     replaceStoreChain(Replacement.first, Replacement.second);
 
   return MadeChangeToSt;
 }
 
 /// This is the entry point for the file.
-void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA,
+void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis *AA,
                            CodeGenOpt::Level OptLevel) {
   /// This is the main entry point to this class.
   DAGCombiner(*this, AA, OptLevel).Run(Level);
 }

llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

public:
   ///
   bool HasTailCall;
 
   LLVMContext *Context;
 
   SelectionDAGBuilder(SelectionDAG &dag, FunctionLoweringInfo &funcinfo,
                       CodeGenOpt::Level ol)
     : CurInst(nullptr), SDNodeOrder(LowestSDNodeOrder), TM(dag.getTarget()),
-      DAG(dag), FuncInfo(funcinfo),
+      DAG(dag), DL(nullptr), AA(nullptr), FuncInfo(funcinfo),
       HasTailCall(false) {
   }
 
-  void init(GCFunctionInfo *gfi, AliasAnalysis &aa,
+  void init(GCFunctionInfo *gfi, AliasAnalysis *AA,
             const TargetLibraryInfo *li);
 
   /// Clear out the current SelectionDAG and the associated state and prepare
   /// this SelectionDAGBuilder object to be used for a new block. This doesn't
   /// clear out information about additional blocks that are needed to complete
   /// switch lowering or PHI node updating; that information is cleared out as
   /// it is consumed.
   void clear();

llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

for (unsigned i = 0; i != NumRegs; ++i) {
       if (TheReg == SP && Code == InlineAsm::Kind_Clobber) {
         // If we clobbered the stack pointer, MFI should know about it.
         assert(DAG.getMachineFunction().getFrameInfo().hasOpaqueSPAdjustment());
       }
     }
   }
 }
 
-void SelectionDAGBuilder::init(GCFunctionInfo *gfi, AliasAnalysis &aa,
+void SelectionDAGBuilder::init(GCFunctionInfo *gfi, AliasAnalysis *aa,
                                const TargetLibraryInfo *li) {
-  AA = &aa;
+  AA = aa;
   GFI = gfi;
   LibInfo = li;
   DL = &DAG.getDataLayout();
   Context = DAG.getContext();
   LPadToCallSiteMap.clear();
 }
 
 void SelectionDAGBuilder::clear() {
void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
   if (NumValues == 0)
     return;
 
   SDValue Root;
   bool ConstantMemory = false;
   if (isVolatile || NumValues > MaxParallelChains)
     // Serialize volatile loads with other side effects.
     Root = getRoot();
-  else if (AA->pointsToConstantMemory(MemoryLocation(
+  else if (AA && AA->pointsToConstantMemory(MemoryLocation(
                SV, DAG.getDataLayout().getTypeStoreSize(Ty), AAInfo))) {
     // Do not serialize (non-volatile) loads of constant memory with anything.
     Root = DAG.getEntryNode();
     ConstantMemory = true;
   } else {
     // Do not serialize non-volatile loads against each other.
     Root = DAG.getRoot();
   }
assert(!I.isVolatile() &&
          I.getMetadata(LLVMContext::MD_nontemporal) == nullptr &&
          I.getMetadata(LLVMContext::MD_invariant_load) == nullptr &&
          "Support volatile, non temporal, invariant for load_from_swift_error");
 
   const Value *SV = I.getOperand(0);
   Type *Ty = I.getType();
   AAMDNodes AAInfo;
   I.getAAMetadata(AAInfo);
-  assert(!AA->pointsToConstantMemory(MemoryLocation(
-             SV, DAG.getDataLayout().getTypeStoreSize(Ty), AAInfo)) &&
+  assert((!AA || !AA->pointsToConstantMemory(MemoryLocation(
+             SV, DAG.getDataLayout().getTypeStoreSize(Ty), AAInfo))) &&
          "load_from_swift_error should not be constant memory");
 
   SmallVector<EVT, 4> ValueVTs;
   SmallVector<uint64_t, 4> Offsets;
   ComputeValueVTs(DAG.getTargetLoweringInfo(), DAG.getDataLayout(), Ty,
                   ValueVTs, &Offsets);
   assert(ValueVTs.size() == 1 && Offsets[0] == 0 &&
          "expect a single EVT for swifterror");
void SelectionDAGBuilder::visitMaskedLoad(const CallInst &I, bool IsExpanding) {
   if (!Alignment)
     Alignment = DAG.getEVTAlignment(VT);
 
   AAMDNodes AAInfo;
   I.getAAMetadata(AAInfo);
   const MDNode *Ranges = I.getMetadata(LLVMContext::MD_range);
 
   // Do not serialize masked loads of constant memory with anything.
-  bool AddToChain = !AA->pointsToConstantMemory(MemoryLocation(
+  bool AddToChain = !AA || !AA->pointsToConstantMemory(MemoryLocation(
       PtrOperand, DAG.getDataLayout().getTypeStoreSize(I.getType()), AAInfo));
   SDValue InChain = AddToChain ? DAG.getRoot() : DAG.getEntryNode();
 
   MachineMemOperand *MMO =
     DAG.getMachineFunction().
     getMachineMemOperand(MachinePointerInfo(PtrOperand),
                           MachineMemOperand::MOLoad,  VT.getStoreSize(),
                           Alignment, AAInfo, Ranges);
void SelectionDAGBuilder::visitMaskedGather(const CallInst &I) {
 
   SDValue Root = DAG.getRoot();
   SDValue Base;
   SDValue Index;
   const Value *BasePtr = Ptr;
   bool UniformBase = getUniformBase(BasePtr, Base, Index, this);
   bool ConstantMemory = false;
   if (UniformBase &&
-      AA->pointsToConstantMemory(MemoryLocation(
+      AA && AA->pointsToConstantMemory(MemoryLocation(
           BasePtr, DAG.getDataLayout().getTypeStoreSize(I.getType()),
           AAInfo))) {
     // Do not serialize (non-volatile) loads of constant memory with anything.
     Root = DAG.getEntryNode();
     ConstantMemory = true;
   }
 
   MachineMemOperand *MMO =
static SDValue getMemCmpLoad(const Value *PtrVal, MVT LoadVT,
   }
 
   // Otherwise, we have to emit the load.  If the pointer is to unfoldable but
   // still constant memory, the input chain can be the entry node.
   SDValue Root;
   bool ConstantMemory = false;
 
   // Do not serialize (non-volatile) loads of constant memory with anything.
-  if (Builder.AA->pointsToConstantMemory(PtrVal)) {
+  if (Builder.AA && Builder.AA->pointsToConstantMemory(PtrVal)) {
     Root = Builder.DAG.getEntryNode();
     ConstantMemory = true;
   } else {
     // Do not serialize non-volatile loads against each other.
     Root = Builder.DAG.getRoot();
   }
 
   SDValue Ptr = Builder.getValue(PtrVal);

llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

 //===----------------------------------------------------------------------===//
 
 SelectionDAGISel::SelectionDAGISel(TargetMachine &tm,
                                    CodeGenOpt::Level OL) :
   MachineFunctionPass(ID), TM(tm),
   FuncInfo(new FunctionLoweringInfo()),
   CurDAG(new SelectionDAG(tm, OL)),
   SDB(new SelectionDAGBuilder(*CurDAG, *FuncInfo, OL)),
-  GFI(),
+  AA(), GFI(),
   OptLevel(OL),
   DAGSize(0) {
     initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
     initializeBranchProbabilityInfoWrapperPassPass(
         *PassRegistry::getPassRegistry());
     initializeAAResultsWrapperPassPass(*PassRegistry::getPassRegistry());
     initializeTargetLibraryInfoWrapperPassPass(
         *PassRegistry::getPassRegistry());
   }
 
 SelectionDAGISel::~SelectionDAGISel() {
   delete SDB;
   delete CurDAG;
   delete FuncInfo;
 }
 
 void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
+  if (OptLevel != CodeGenOpt::None)
     AU.addRequired<AAResultsWrapperPass>();
   AU.addRequired<GCModuleInfo>();
   AU.addRequired<StackProtector>();
   AU.addPreserved<StackProtector>();
   AU.addPreserved<GCModuleInfo>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
   if (UseMBPI && OptLevel != CodeGenOpt::None)
     AU.addRequired<BranchProbabilityInfoWrapperPass>();
   MachineFunctionPass::getAnalysisUsage(AU);
bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
   CodeGenOpt::Level NewOptLevel = OptLevel;
   if (OptLevel != CodeGenOpt::None && skipFunction(Fn))
     NewOptLevel = CodeGenOpt::None;
   OptLevelChanger OLC(*this, NewOptLevel);
 
   TII = MF->getSubtarget().getInstrInfo();
   TLI = MF->getSubtarget().getTargetLowering();
   RegInfo = &MF->getRegInfo();
-  AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
   LibInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
   GFI = Fn.hasGC() ? &getAnalysis<GCModuleInfo>().getFunctionInfo(Fn) : nullptr;
   ORE = make_unique<OptimizationRemarkEmitter>(&Fn);
 
   DEBUG(dbgs() << "\n\n\n=== " << Fn.getName() << "\n");
 
   SplitCriticalSideEffectEdges(const_cast<Function &>(Fn));
 
   CurDAG->init(*MF, *ORE);
   FuncInfo->set(Fn, *MF, CurDAG);
 
+  // Now get the optional analyzes if we want to.
+  // This is based on the possibly changed OptLevel (after optnone is taken
+  // into account).  That's unfortunate but OK because it just means we won't
+  // ask for passes that have been required anyway.
+
   if (UseMBPI && OptLevel != CodeGenOpt::None)
     FuncInfo->BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
   else
     FuncInfo->BPI = nullptr;
 
-  SDB->init(GFI, *AA, LibInfo);
+  if (OptLevel != CodeGenOpt::None)
+    AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
+  else
+    AA = nullptr;
+
+  SDB->init(GFI, AA, LibInfo);
 
   MF->setHasInlineAsm(false);
 
   FuncInfo->SplitCSR = false;
 
   // We split CSR if the target supports it for the given function
   // and the function has only return exits.
   if (OptLevel != CodeGenOpt::None && TLI->supportSplitCSR(MF)) {
#endif
 
   if (ViewDAGCombine1 && MatchFilterBB)
     CurDAG->viewGraph("dag-combine1 input for " + BlockName);
 
   // Run the DAG combiner in pre-legalize mode.
   {
     NamedRegionTimer T("combine1", "DAG Combining 1", GroupName,
                        GroupDescription, TimePassesIsEnabled);
-    CurDAG->Combine(BeforeLegalizeTypes, *AA, OptLevel);
+    CurDAG->Combine(BeforeLegalizeTypes, AA, OptLevel);
   }
 
   DEBUG(dbgs() << "Optimized lowered selection DAG: BB#" << BlockNumber
         << " '" << BlockName << "'\n"; CurDAG->dump());
 
   // Second step, hack on the DAG until it only uses operations and types that
   // the target supports.
   if (ViewLegalizeTypesDAGs && MatchFilterBB)
#endif
   if (Changed) {
     if (ViewDAGCombineLT && MatchFilterBB)
       CurDAG->viewGraph("dag-combine-lt input for " + BlockName);
 
     // Run the DAG combiner in post-type-legalize mode.
     {
       NamedRegionTimer T("combine_lt", "DAG Combining after legalize types",
                          GroupName, GroupDescription, TimePassesIsEnabled);
-      CurDAG->Combine(AfterLegalizeTypes, *AA, OptLevel);
+      CurDAG->Combine(AfterLegalizeTypes, AA, OptLevel);
     }
 
     DEBUG(dbgs() << "Optimized type-legalized selection DAG: BB#" << BlockNumber
           << " '" << BlockName << "'\n"; CurDAG->dump());
 
   }
 
   {
if (Changed) {
 
     if (ViewDAGCombineLT && MatchFilterBB)
       CurDAG->viewGraph("dag-combine-lv input for " + BlockName);
 
     // Run the DAG combiner in post-type-legalize mode.
     {
       NamedRegionTimer T("combine_lv", "DAG Combining after legalize vectors",
                          GroupName, GroupDescription, TimePassesIsEnabled);
-      CurDAG->Combine(AfterLegalizeVectorOps, *AA, OptLevel);
+      CurDAG->Combine(AfterLegalizeVectorOps, AA, OptLevel);
     }
 
     DEBUG(dbgs() << "Optimized vector-legalized selection DAG: BB#"
           << BlockNumber << " '" << BlockName << "'\n"; CurDAG->dump());
   }
 
   if (ViewLegalizeDAGs && MatchFilterBB)
     CurDAG->viewGraph("legalize input for " + BlockName);
#endif
 
   if (ViewDAGCombine2 && MatchFilterBB)
     CurDAG->viewGraph("dag-combine2 input for " + BlockName);
 
   // Run the DAG combiner in post-legalize mode.
   {
     NamedRegionTimer T("combine2", "DAG Combining 2", GroupName,
                        GroupDescription, TimePassesIsEnabled);
-    CurDAG->Combine(AfterLegalizeDAG, *AA, OptLevel);
+    CurDAG->Combine(AfterLegalizeDAG, AA, OptLevel);
   }
 
   DEBUG(dbgs() << "Optimized legalized selection DAG: BB#" << BlockNumber
         << " '" << BlockName << "'\n"; CurDAG->dump());
 
   if (OptLevel != CodeGenOpt::None)
     ComputeLiveOutVRegInfo();
 

llvm/trunk/test/CodeGen/X86/O0-pipeline.ll

 ; CHECK-NEXT:       Inserts calls to mcount-like functions
 ; CHECK-NEXT:     Rewrite Symbols
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Dominator Tree Construction
 ; CHECK-NEXT:       Exception handling preparation
 ; CHECK-NEXT:       Safe Stack instrumentation pass
 ; CHECK-NEXT:       Insert stack protectors
 ; CHECK-NEXT:       Module Verifier
-; CHECK-NEXT:       Dominator Tree Construction
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       X86 DAG->DAG Instruction Selection
 ; CHECK-NEXT:       X86 PIC Global Base Reg Initialization
 ; CHECK-NEXT:       Expand ISel Pseudo-instructions
 ; CHECK-NEXT:       Local Stack Slot Allocation
 ; CHECK-NEXT:       X86 WinAlloca Expander
 ; CHECK-NEXT:       Eliminate PHI nodes for register allocation
+; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Two-Address instruction pass
 ; CHECK-NEXT:       Fast Register Allocator
 ; CHECK-NEXT:       Bundle Machine CFG Edges
 ; CHECK-NEXT:       X86 FP Stackifier
 ; CHECK-NEXT:       Prologue/Epilogue Insertion & Frame Finalization
 ; CHECK-NEXT:       Post-RA pseudo instruction expansion pass
 ; CHECK-NEXT:       X86 pseudo instruction expansion pass
 ; CHECK-NEXT:       Analyze Machine Code For Garbage Collection

llvm/trunk/test/CodeGen/X86/pr32284.ll

 ; X86-NEXT:    addl $8, %esp
 ; X86-NEXT:    retl
 ;
 ; X86-O0-LABEL: foo:
 ; X86-O0:       # BB#0: # %entry
 ; X86-O0-NEXT:    subl $12, %esp
 ; X86-O0-NEXT:  .Lcfi0:
 ; X86-O0-NEXT:    .cfi_def_cfa_offset 16
-; X86-O0-NEXT:    movzbl c, %eax
-; X86-O0-NEXT:    testl %eax, %eax
-; X86-O0-NEXT:    setne %cl
-; X86-O0-NEXT:    movl %eax, %edx
-; X86-O0-NEXT:    movb %dl, %ch
-; X86-O0-NEXT:    testb %ch, %ch
+; X86-O0-NEXT:    movb c, %al
+; X86-O0-NEXT:    testb %al, %al
 ; X86-O0-NEXT:    setne {{[0-9]+}}(%esp)
-; X86-O0-NEXT:    movzbl %cl, %edx
-; X86-O0-NEXT:    subl %eax, %edx
-; X86-O0-NEXT:    setle %cl
-; X86-O0-NEXT:    # implicit-def: %EAX
-; X86-O0-NEXT:    movb %cl, %al
-; X86-O0-NEXT:    andl $1, %eax
-; X86-O0-NEXT:    kmovd %eax, %k0
-; X86-O0-NEXT:    kmovd %k0, %eax
+; X86-O0-NEXT:    movzbl c, %ecx
+; X86-O0-NEXT:    testl %ecx, %ecx
+; X86-O0-NEXT:    setne %al
+; X86-O0-NEXT:    movzbl %al, %edx
+; X86-O0-NEXT:    subl %ecx, %edx
+; X86-O0-NEXT:    setle %al
+; X86-O0-NEXT:    # implicit-def: %ECX
 ; X86-O0-NEXT:    movb %al, %cl
-; X86-O0-NEXT:    andb $1, %cl
-; X86-O0-NEXT:    movzbl %cl, %eax
-; X86-O0-NEXT:    movl %eax, {{[0-9]+}}(%esp)
+; X86-O0-NEXT:    andl $1, %ecx
+; X86-O0-NEXT:    kmovd %ecx, %k0
+; X86-O0-NEXT:    kmovd %k0, %ecx
+; X86-O0-NEXT:    movb %cl, %al
+; X86-O0-NEXT:    andb $1, %al
+; X86-O0-NEXT:    movzbl %al, %ecx
+; X86-O0-NEXT:    movl %ecx, {{[0-9]+}}(%esp)
 ; X86-O0-NEXT:    movl %edx, (%esp) # 4-byte Spill
 ; X86-O0-NEXT:    addl $12, %esp
 ; X86-O0-NEXT:    retl
 ;
 ; X64-LABEL: foo:
 ; X64:       # BB#0: # %entry
 ; X64-NEXT:    movzbl {{.*}}(%rip), %eax
 ; X64-NEXT:    testb %al, %al
 ; X64-NEXT:    setne -{{[0-9]+}}(%rsp)
 ; X64-NEXT:    xorl %ecx, %ecx
 ; X64-NEXT:    testl %eax, %eax
 ; X64-NEXT:    setne %cl
 ; X64-NEXT:    xorl %edx, %edx
 ; X64-NEXT:    cmpl %eax, %ecx
 ; X64-NEXT:    setle %dl
 ; X64-NEXT:    movl %edx, -{{[0-9]+}}(%rsp)
 ; X64-NEXT:    retq
 ;
 ; X64-O0-LABEL: foo:
 ; X64-O0:       # BB#0: # %entry
-; X64-O0-NEXT:    movzbl {{.*}}(%rip), %eax
-; X64-O0-NEXT:    movl %eax, %ecx
-; X64-O0-NEXT:    movb %cl, %dl
-; X64-O0-NEXT:    movl %ecx, %eax
-; X64-O0-NEXT:    testq %rcx, %rcx
-; X64-O0-NEXT:    setne %sil
-; X64-O0-NEXT:    testb %dl, %dl
+; X64-O0-NEXT:    movb {{.*}}(%rip), %al
+; X64-O0-NEXT:    testb %al, %al
 ; X64-O0-NEXT:    setne -{{[0-9]+}}(%rsp)
-; X64-O0-NEXT:    movzbl %sil, %edi
-; X64-O0-NEXT:    subl %eax, %edi
-; X64-O0-NEXT:    setle %dl
-; X64-O0-NEXT:    # implicit-def: %EAX
-; X64-O0-NEXT:    movb %dl, %al
-; X64-O0-NEXT:    andl $1, %eax
-; X64-O0-NEXT:    kmovd %eax, %k0
-; X64-O0-NEXT:    kmovd %k0, %eax
-; X64-O0-NEXT:    movb %al, %dl
-; X64-O0-NEXT:    andb $1, %dl
-; X64-O0-NEXT:    movzbl %dl, %eax
-; X64-O0-NEXT:    movl %eax, -{{[0-9]+}}(%rsp)
-; X64-O0-NEXT:    movl %edi, -{{[0-9]+}}(%rsp) # 4-byte Spill
+; X64-O0-NEXT:    movzbl {{.*}}(%rip), %ecx
+; X64-O0-NEXT:    testl %ecx, %ecx
+; X64-O0-NEXT:    setne %al
+; X64-O0-NEXT:    movzbl %al, %edx
+; X64-O0-NEXT:    subl %ecx, %edx
+; X64-O0-NEXT:    setle %al
+; X64-O0-NEXT:    # implicit-def: %ECX
+; X64-O0-NEXT:    movb %al, %cl
+; X64-O0-NEXT:    andl $1, %ecx
+; X64-O0-NEXT:    kmovd %ecx, %k0
+; X64-O0-NEXT:    kmovd %k0, %ecx
+; X64-O0-NEXT:    movb %cl, %al
+; X64-O0-NEXT:    andb $1, %al
+; X64-O0-NEXT:    movzbl %al, %ecx
+; X64-O0-NEXT:    movl %ecx, -{{[0-9]+}}(%rsp)
+; X64-O0-NEXT:    movl %edx, -{{[0-9]+}}(%rsp) # 4-byte Spill
 ; X64-O0-NEXT:    retq
 entry:
   %a = alloca i8, align 1
   %b = alloca i32, align 4
   %0 = load i8, i8* @c, align 1
   %conv = zext i8 %0 to i32
   %sub = sub nsw i32 0, %conv
   %conv1 = sext i32 %sub to i64