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https://github.com/RPCS3/llvm-mirror.git
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Revert "[CodeGen] Omit range checks from jump tables when lowering switches with unreachable default"
This reverts commit 2a0f2c5ef3330846149598220467d9f3c6e8b99c (r355490).
The commit causes an assertion failure when compiling LLVM code:
$ cat repro.cpp
class QQQ {
public:
bool x() const;
bool y() const;
unsigned getSizeInBits() const {
if (y() || x())
return getScalarSizeInBits();
return getScalarSizeInBits() * 2;
}
unsigned getScalarSizeInBits() const;
};
int f(const QQQ &Ty) {
switch (Ty.getSizeInBits()) {
case 1:
case 8:
return 0;
case 16:
return 1;
case 32:
return 2;
case 64:
return 3;
default:
__builtin_unreachable();
}
}
$ clang -O2 -o repro.o repro.cpp
assert.h assertion failed at llvm/include/llvm/ADT/ilist_iterator.h:139 in llvm::ilist_iterator::reference llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::MachineInstr, true, true, void>, true, false>::operator*() const [OptionsT = llvm::ilist_detail::node_options<llvm::MachineInstr, true, true, void>, IsReverse = true, IsConst = false]: !NodePtr->isKnownSentinel()
*** Check failure stack trace: ***
@ 0x558aab4afc10 __assert_fail
@ 0x558aa885479b llvm::ilist_iterator<>::operator*()
@ 0x558aa8854715 llvm::MachineInstrBundleIterator<>::operator*()
@ 0x558aa92c33c3 llvm::X86InstrInfo::optimizeCompareInstr()
@ 0x558aa9a9c251 (anonymous namespace)::PeepholeOptimizer::optimizeCmpInstr()
@ 0x558aa9a9b371 (anonymous namespace)::PeepholeOptimizer::runOnMachineFunction()
@ 0x558aa99a4fc8 llvm::MachineFunctionPass::runOnFunction()
@ 0x558aab019fc4 llvm::FPPassManager::runOnFunction()
@ 0x558aab01a3a5 llvm::FPPassManager::runOnModule()
@ 0x558aab01aa9b (anonymous namespace)::MPPassManager::runOnModule()
@ 0x558aab01a635 llvm::legacy::PassManagerImpl::run()
@ 0x558aab01afe1 llvm::legacy::PassManager::run()
@ 0x558aa5914769 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly()
@ 0x558aa5910f44 clang::EmitBackendOutput()
@ 0x558aa5906135 clang::BackendConsumer::HandleTranslationUnit()
@ 0x558aa6d165ad clang::ParseAST()
@ 0x558aa6a94e22 clang::ASTFrontendAction::ExecuteAction()
@ 0x558aa590255d clang::CodeGenAction::ExecuteAction()
@ 0x558aa6a94840 clang::FrontendAction::Execute()
@ 0x558aa6a38cca clang::CompilerInstance::ExecuteAction()
@ 0x558aa4e2294b clang::ExecuteCompilerInvocation()
@ 0x558aa4df6200 cc1_main()
@ 0x558aa4e1b37f ExecuteCC1Tool()
@ 0x558aa4e1a725 main
@ 0x7ff20d56abbd __libc_start_main
@ 0x558aa4df51c9 _start
llvm-svn: 355515
This commit is contained in:
Alexander Kornienko
parent
db7c2e63ef
commit
7dffb4905c
@ -2388,31 +2388,24 @@ void SelectionDAGBuilder::visitJumpTableHeader(JumpTable &JT,
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JumpTableReg, SwitchOp);
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JT.Reg = JumpTableReg;
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if (!JTH.OmitRangeCheck) {
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// Emit the range check for the jump table, and branch to the default block
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// for the switch statement if the value being switched on exceeds the
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// largest case in the switch.
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SDValue CMP = DAG.getSetCC(
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dl, TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(),
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Sub.getValueType()),
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Sub, DAG.getConstant(JTH.Last - JTH.First, dl, VT), ISD::SETUGT);
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// Emit the range check for the jump table, and branch to the default block
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// for the switch statement if the value being switched on exceeds the largest
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// case in the switch.
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SDValue CMP = DAG.getSetCC(
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dl, TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(),
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Sub.getValueType()),
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Sub, DAG.getConstant(JTH.Last - JTH.First, dl, VT), ISD::SETUGT);
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SDValue BrCond = DAG.getNode(ISD::BRCOND, dl,
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MVT::Other, CopyTo, CMP,
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DAG.getBasicBlock(JT.Default));
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SDValue BrCond = DAG.getNode(ISD::BRCOND, dl,
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MVT::Other, CopyTo, CMP,
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DAG.getBasicBlock(JT.Default));
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// Avoid emitting unnecessary branches to the next block.
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if (JT.MBB != NextBlock(SwitchBB))
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BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, BrCond,
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DAG.getBasicBlock(JT.MBB));
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DAG.setRoot(BrCond);
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} else {
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SDValue BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, CopyTo,
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DAG.getBasicBlock(JT.MBB));
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DAG.setRoot(BrCond);
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SwitchBB->removeSuccessor(JT.Default, true);
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}
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// Avoid emitting unnecessary branches to the next block.
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if (JT.MBB != NextBlock(SwitchBB))
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BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, BrCond,
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DAG.getBasicBlock(JT.MBB));
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DAG.setRoot(BrCond);
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}
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/// Create a LOAD_STACK_GUARD node, and let it carry the target specific global
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@ -9797,13 +9790,10 @@ bool SelectionDAGBuilder::buildJumpTable(const CaseClusterVector &Clusters,
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->createJumpTableIndex(Table);
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// Set up the jump table info.
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bool UnreachableDefault =
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isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg());
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bool OmitRangeCheck = UnreachableDefault;
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JumpTable JT(-1U, JTI, JumpTableMBB, nullptr);
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JumpTableHeader JTH(Clusters[First].Low->getValue(),
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Clusters[Last].High->getValue(), SI->getCondition(),
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nullptr, false, OmitRangeCheck);
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nullptr, false);
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JTCases.emplace_back(std::move(JTH), std::move(JT));
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JTCluster = CaseCluster::jumpTable(Clusters[First].Low, Clusters[Last].High,
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@ -10609,6 +10599,38 @@ void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) {
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// if there are many clusters.
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sortAndRangeify(Clusters);
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if (TM.getOptLevel() != CodeGenOpt::None) {
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// Replace an unreachable default with the most popular destination.
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// FIXME: Exploit unreachable default more aggressively.
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bool UnreachableDefault =
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isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg());
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if (UnreachableDefault && !Clusters.empty()) {
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DenseMap<const BasicBlock *, unsigned> Popularity;
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unsigned MaxPop = 0;
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const BasicBlock *MaxBB = nullptr;
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for (auto I : SI.cases()) {
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const BasicBlock *BB = I.getCaseSuccessor();
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if (++Popularity[BB] > MaxPop) {
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MaxPop = Popularity[BB];
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MaxBB = BB;
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}
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}
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// Set new default.
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assert(MaxPop > 0 && MaxBB);
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DefaultMBB = FuncInfo.MBBMap[MaxBB];
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// Remove cases that were pointing to the destination that is now the
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// default.
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CaseClusterVector New;
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New.reserve(Clusters.size());
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for (CaseCluster &CC : Clusters) {
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if (CC.MBB != DefaultMBB)
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New.push_back(CC);
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}
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Clusters = std::move(New);
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}
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}
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// The branch probablity of the peeled case.
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BranchProbability PeeledCaseProb = BranchProbability::getZero();
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MachineBasicBlock *PeeledSwitchMBB =
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@ -277,12 +277,11 @@ private:
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const Value *SValue;
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MachineBasicBlock *HeaderBB;
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bool Emitted;
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bool OmitRangeCheck;
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JumpTableHeader(APInt F, APInt L, const Value *SV, MachineBasicBlock *H,
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bool E = false, bool ORC = false)
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bool E = false)
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: First(std::move(F)), Last(std::move(L)), SValue(SV), HeaderBB(H),
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Emitted(E), OmitRangeCheck(ORC) {}
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Emitted(E) {}
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};
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using JumpTableBlock = std::pair<JumpTableHeader, JumpTable>;
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@ -1,63 +0,0 @@
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; RUN: llc -O3 -o - %s | FileCheck %s
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; Test that the output in the presence of an unreachable default does not have
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; a compare and branch at the top of the switch to handle the default case.
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target triple = "aarch64-unknown-linux-gnu"
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; Function Attrs: nounwind
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define void @fn(i4) {
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switch i4 %0, label %default [
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i4 0, label %case_0
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i4 1, label %case_1
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i4 2, label %case_2
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i4 3, label %case_3
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i4 4, label %case_4
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i4 5, label %case_5
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]
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; CHECK-LABEL: fn:
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; CHECK-NOT: sub
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; CHECK-NOT: cmp
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; CHECK-NOT: b.hi
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; CHECK: ldrb {{w[0-9]+}}, [{{x[0-9]+}}, {{x[0-9]+}}]
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; CHECK: add {{x[0-9]+}}, {{x[0-9]+}}, {{x[0-9]+}}, lsl #2
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; CHECK: br {{x[0-9]+}}
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default:
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unreachable
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case_0:
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tail call void @handle_case_00(i4 %0) #2
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br label %return_label
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case_1:
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tail call void @handle_case_01(i4 %0) #2
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br label %return_label
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case_2:
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tail call void @handle_case_02(i4 %0) #2
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br label %return_label
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case_3:
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tail call void @handle_case_03(i4 %0) #2
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br label %return_label
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case_4:
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tail call void @handle_case_04(i4 %0) #2
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br label %return_label
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case_5:
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tail call void @handle_case_05(i4 %0) #2
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br label %return_label
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return_label:
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ret void
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}
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declare void @handle_case_00(i4)
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declare void @handle_case_01(i4)
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declare void @handle_case_02(i4)
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declare void @handle_case_03(i4)
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declare void @handle_case_04(i4)
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declare void @handle_case_05(i4)
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@ -18,43 +18,41 @@ declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture r
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define void @pr38743() #1 align 2 {
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; CHECK-LABEL: pr38743:
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; CHECK: # %bb.0: # %bb
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; CHECK-NEXT: xorl %eax, %eax
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; CHECK-NEXT: jmpq *.LJTI0_0(,%rax,8)
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; CHECK-NEXT: .[[LABEL1:[A-Z_0-9]+]]: # %bb5
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; CHECK-NEXT: movzwl .str.17+{{.*}}(%rip), %eax
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; CHECK-NEXT: movw %ax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq .str.17(%rip), %rax
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; CHECK-NEXT: jmp .[[LABEL4:[A-Z_0-9]+]]
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; CHECK-NEXT: .[[LABEL2:[A-Z_0-9]+]]: # %bb2
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; CHECK-NEXT: movq .str.16+{{.*}}(%rip), %rax
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; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq .str.16(%rip), %rax
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; CHECK-NEXT: jmp .[[LABEL4]]
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; CHECK-NEXT: .[[LABEL3:[A-Z_0-9]+]]: # %bb8
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; CHECK-NEXT: movq .str.18+{{.*}}(%rip), %rax
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; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq .str.18(%rip), %rax
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; CHECK-NEXT: .[[LABEL4]]: # %bb12
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; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rax
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; CHECK-NEXT: movq %rax, (%rax)
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; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %al
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; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rcx
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; CHECK-NEXT: movzwl -{{[0-9]+}}(%rsp), %edx
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; CHECK-NEXT: movl -{{[0-9]+}}(%rsp), %esi
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; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %dil
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; CHECK-NEXT: movb %al, (%rax)
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; CHECK-NEXT: movq %rcx, {{[0-9]+}}(%rax)
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; CHECK-NEXT: movw %dx, {{[0-9]+}}(%rax)
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; CHECK-NEXT: movl %esi, {{[0-9]+}}(%rax)
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; CHECK-NEXT: movb %dil, {{[0-9]+}}(%rax)
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; CHECK-NEXT: retq
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; CHECK-LABEL: .LJTI0_0:
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; CHECK: .quad .[[LABEL2]]
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; CHECK-NEXT: .quad .[[LABEL1]]
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; CHECK-NEXT: .quad .[[LABEL3]]
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; CHECK-NEXT: .quad .[[LABEL1]]
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; CHECK: # %bb.0: # %bb
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; CHECK-NEXT: cmpl $3, %eax
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; CHECK-NEXT: je .LBB0_4
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; CHECK-NEXT: # %bb.1: # %bb
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; CHECK-NEXT: cmpl $1, %eax
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; CHECK-NEXT: je .LBB0_2
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; CHECK-NEXT: # %bb.3: # %bb5
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; CHECK-NEXT: movzwl .str.17+{{.*}}(%rip), %eax
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; CHECK-NEXT: movw %ax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq {{.*}}(%rip), %rax
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; CHECK-NEXT: jmp .LBB0_5
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; CHECK-NEXT: .LBB0_4: # %bb8
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; CHECK-NEXT: movq .str.18+{{.*}}(%rip), %rax
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; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq {{.*}}(%rip), %rax
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; CHECK-NEXT: jmp .LBB0_5
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; CHECK-NEXT: .LBB0_2: # %bb2
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; CHECK-NEXT: movq .str.16+{{.*}}(%rip), %rax
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; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq {{.*}}(%rip), %rax
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; CHECK-NEXT: .LBB0_5: # %bb12
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; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp)
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; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rax
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; CHECK-NEXT: movq %rax, (%rax)
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; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %al
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; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rcx
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; CHECK-NEXT: movzwl -{{[0-9]+}}(%rsp), %edx
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; CHECK-NEXT: movl -{{[0-9]+}}(%rsp), %esi
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; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %dil
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; CHECK-NEXT: movb %al, (%rax)
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; CHECK-NEXT: movq %rcx, 1(%rax)
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; CHECK-NEXT: movw %dx, 9(%rax)
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; CHECK-NEXT: movl %esi, 11(%rax)
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; CHECK-NEXT: movb %dil, 15(%rax)
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; CHECK-NEXT: retq
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bb:
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%tmp = alloca %0, align 16
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%tmp1 = bitcast %0* %tmp to i8*
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@ -2,12 +2,14 @@
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; RUN: llc -mtriple=i686-pc-gnu-linux -print-machineinstrs=expand-isel-pseudos %s -o /dev/null 2>&1 | FileCheck %s -check-prefix=CHECK-JT-PROB
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; An unreachable default destination is ignored and no compare and branch
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; is generated for the default values.
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; An unreachable default destination is replaced with the most popular case label.
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define void @foo(i32 %x, i32* %to) {
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; CHECK-LABEL: foo:
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; CHECK: movl 4(%esp), [[REG:%e[a-z]{2}]]
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; CHECK: cmpl $3, [[REG]]
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; CHECK: ja .LBB0_6
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; CHECK-NEXT: # %bb.1:
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; CHECK-NEXT: jmpl *.LJTI0_0(,[[REG]],4)
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; CHECK: movl $4
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; CHECK: retl
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@ -43,12 +45,10 @@ default:
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; The jump table has four entries.
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; CHECK-LABEL: .LJTI0_0:
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; CHECK-NEXT: .long .LBB0_1
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; CHECK-NEXT: .long .LBB0_2
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; CHECK-NEXT: .long .LBB0_3
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; CHECK-NEXT: .long .LBB0_4
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; CHECK-NEXT: .long .LBB0_5
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; CHECK-NEXT: .long .LBB0_5
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}
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; Check if branch probabilities are correctly assigned to the jump table.
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