diff options
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 80 | ||||
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h | 5 | ||||
| -rw-r--r-- | llvm/test/CodeGen/AArch64/switch-unreachable-default.ll | 63 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/pr38743.ll | 72 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/switch-jump-table.ll | 8 |
5 files changed, 92 insertions, 136 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 52b039eb44f..33921a2c56d 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -2388,31 +2388,24 @@ void SelectionDAGBuilder::visitJumpTableHeader(JumpTable &JT, JumpTableReg, SwitchOp); JT.Reg = JumpTableReg; - if (!JTH.OmitRangeCheck) { - // Emit the range check for the jump table, and branch to the default block - // for the switch statement if the value being switched on exceeds the - // largest case in the switch. - SDValue CMP = DAG.getSetCC( - dl, TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), - Sub.getValueType()), - Sub, DAG.getConstant(JTH.Last - JTH.First, dl, VT), ISD::SETUGT); - - SDValue BrCond = DAG.getNode(ISD::BRCOND, dl, - MVT::Other, CopyTo, CMP, - DAG.getBasicBlock(JT.Default)); - - // Avoid emitting unnecessary branches to the next block. - if (JT.MBB != NextBlock(SwitchBB)) - BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, BrCond, - DAG.getBasicBlock(JT.MBB)); - - DAG.setRoot(BrCond); - } else { - SDValue BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, CopyTo, - DAG.getBasicBlock(JT.MBB)); - DAG.setRoot(BrCond); - SwitchBB->removeSuccessor(JT.Default, true); - } + // Emit the range check for the jump table, and branch to the default block + // for the switch statement if the value being switched on exceeds the largest + // case in the switch. + SDValue CMP = DAG.getSetCC( + dl, TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), + Sub.getValueType()), + Sub, DAG.getConstant(JTH.Last - JTH.First, dl, VT), ISD::SETUGT); + + SDValue BrCond = DAG.getNode(ISD::BRCOND, dl, + MVT::Other, CopyTo, CMP, + DAG.getBasicBlock(JT.Default)); + + // Avoid emitting unnecessary branches to the next block. + if (JT.MBB != NextBlock(SwitchBB)) + BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, BrCond, + DAG.getBasicBlock(JT.MBB)); + + DAG.setRoot(BrCond); } /// Create a LOAD_STACK_GUARD node, and let it carry the target specific global @@ -9797,13 +9790,10 @@ bool SelectionDAGBuilder::buildJumpTable(const CaseClusterVector &Clusters, ->createJumpTableIndex(Table); // Set up the jump table info. - bool UnreachableDefault = - isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg()); - bool OmitRangeCheck = UnreachableDefault; JumpTable JT(-1U, JTI, JumpTableMBB, nullptr); JumpTableHeader JTH(Clusters[First].Low->getValue(), Clusters[Last].High->getValue(), SI->getCondition(), - nullptr, false, OmitRangeCheck); + nullptr, false); JTCases.emplace_back(std::move(JTH), std::move(JT)); JTCluster = CaseCluster::jumpTable(Clusters[First].Low, Clusters[Last].High, @@ -10609,6 +10599,38 @@ void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) { // if there are many clusters. sortAndRangeify(Clusters); + if (TM.getOptLevel() != CodeGenOpt::None) { + // Replace an unreachable default with the most popular destination. + // FIXME: Exploit unreachable default more aggressively. + bool UnreachableDefault = + isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg()); + if (UnreachableDefault && !Clusters.empty()) { + DenseMap<const BasicBlock *, unsigned> Popularity; + unsigned MaxPop = 0; + const BasicBlock *MaxBB = nullptr; + for (auto I : SI.cases()) { + const BasicBlock *BB = I.getCaseSuccessor(); + if (++Popularity[BB] > MaxPop) { + MaxPop = Popularity[BB]; + MaxBB = BB; + } + } + // Set new default. + assert(MaxPop > 0 && MaxBB); + DefaultMBB = FuncInfo.MBBMap[MaxBB]; + + // Remove cases that were pointing to the destination that is now the + // default. + CaseClusterVector New; + New.reserve(Clusters.size()); + for (CaseCluster &CC : Clusters) { + if (CC.MBB != DefaultMBB) + New.push_back(CC); + } + Clusters = std::move(New); + } + } + // The branch probablity of the peeled case. BranchProbability PeeledCaseProb = BranchProbability::getZero(); MachineBasicBlock *PeeledSwitchMBB = diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h index 09dd7afd925..e84214dbf5e 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h @@ -277,12 +277,11 @@ private: const Value *SValue; MachineBasicBlock *HeaderBB; bool Emitted; - bool OmitRangeCheck; JumpTableHeader(APInt F, APInt L, const Value *SV, MachineBasicBlock *H, - bool E = false, bool ORC = false) + bool E = false) : First(std::move(F)), Last(std::move(L)), SValue(SV), HeaderBB(H), - Emitted(E), OmitRangeCheck(ORC) {} + Emitted(E) {} }; using JumpTableBlock = std::pair<JumpTableHeader, JumpTable>; diff --git a/llvm/test/CodeGen/AArch64/switch-unreachable-default.ll b/llvm/test/CodeGen/AArch64/switch-unreachable-default.ll deleted file mode 100644 index ce11c14d1ca..00000000000 --- a/llvm/test/CodeGen/AArch64/switch-unreachable-default.ll +++ /dev/null @@ -1,63 +0,0 @@ -; RUN: llc -O3 -o - %s | FileCheck %s - -; Test that the output in the presence of an unreachable default does not have -; a compare and branch at the top of the switch to handle the default case. - -target triple = "aarch64-unknown-linux-gnu" - -; Function Attrs: nounwind -define void @fn(i4) { - switch i4 %0, label %default [ - i4 0, label %case_0 - i4 1, label %case_1 - i4 2, label %case_2 - i4 3, label %case_3 - i4 4, label %case_4 - i4 5, label %case_5 - ] - -; CHECK-LABEL: fn: -; CHECK-NOT: sub -; CHECK-NOT: cmp -; CHECK-NOT: b.hi -; CHECK: ldrb {{w[0-9]+}}, [{{x[0-9]+}}, {{x[0-9]+}}] -; CHECK: add {{x[0-9]+}}, {{x[0-9]+}}, {{x[0-9]+}}, lsl #2 -; CHECK: br {{x[0-9]+}} - -default: - unreachable - -case_0: - tail call void @handle_case_00(i4 %0) #2 - br label %return_label - -case_1: - tail call void @handle_case_01(i4 %0) #2 - br label %return_label - -case_2: - tail call void @handle_case_02(i4 %0) #2 - br label %return_label - -case_3: - tail call void @handle_case_03(i4 %0) #2 - br label %return_label - -case_4: - tail call void @handle_case_04(i4 %0) #2 - br label %return_label - -case_5: - tail call void @handle_case_05(i4 %0) #2 - br label %return_label - -return_label: - ret void -} - -declare void @handle_case_00(i4) -declare void @handle_case_01(i4) -declare void @handle_case_02(i4) -declare void @handle_case_03(i4) -declare void @handle_case_04(i4) -declare void @handle_case_05(i4) diff --git a/llvm/test/CodeGen/X86/pr38743.ll b/llvm/test/CodeGen/X86/pr38743.ll index 97fe277405e..ac5d48ef5f5 100644 --- a/llvm/test/CodeGen/X86/pr38743.ll +++ b/llvm/test/CodeGen/X86/pr38743.ll @@ -18,43 +18,41 @@ declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture r define void @pr38743() #1 align 2 { ; CHECK-LABEL: pr38743: -; CHECK: # %bb.0: # %bb -; CHECK-NEXT: xorl %eax, %eax -; CHECK-NEXT: jmpq *.LJTI0_0(,%rax,8) -; CHECK-NEXT: .[[LABEL1:[A-Z_0-9]+]]: # %bb5 -; CHECK-NEXT: movzwl .str.17+{{.*}}(%rip), %eax -; CHECK-NEXT: movw %ax, -{{[0-9]+}}(%rsp) -; CHECK-NEXT: movq .str.17(%rip), %rax -; CHECK-NEXT: jmp .[[LABEL4:[A-Z_0-9]+]] -; CHECK-NEXT: .[[LABEL2:[A-Z_0-9]+]]: # %bb2 -; CHECK-NEXT: movq .str.16+{{.*}}(%rip), %rax -; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp) -; CHECK-NEXT: movq .str.16(%rip), %rax -; CHECK-NEXT: jmp .[[LABEL4]] -; CHECK-NEXT: .[[LABEL3:[A-Z_0-9]+]]: # %bb8 -; CHECK-NEXT: movq .str.18+{{.*}}(%rip), %rax -; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp) -; CHECK-NEXT: movq .str.18(%rip), %rax -; CHECK-NEXT: .[[LABEL4]]: # %bb12 -; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp) -; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rax -; CHECK-NEXT: movq %rax, (%rax) -; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %al -; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rcx -; CHECK-NEXT: movzwl -{{[0-9]+}}(%rsp), %edx -; CHECK-NEXT: movl -{{[0-9]+}}(%rsp), %esi -; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %dil -; CHECK-NEXT: movb %al, (%rax) -; CHECK-NEXT: movq %rcx, {{[0-9]+}}(%rax) -; CHECK-NEXT: movw %dx, {{[0-9]+}}(%rax) -; CHECK-NEXT: movl %esi, {{[0-9]+}}(%rax) -; CHECK-NEXT: movb %dil, {{[0-9]+}}(%rax) -; CHECK-NEXT: retq -; CHECK-LABEL: .LJTI0_0: -; CHECK: .quad .[[LABEL2]] -; CHECK-NEXT: .quad .[[LABEL1]] -; CHECK-NEXT: .quad .[[LABEL3]] -; CHECK-NEXT: .quad .[[LABEL1]] +; CHECK: # %bb.0: # %bb +; CHECK-NEXT: cmpl $3, %eax +; CHECK-NEXT: je .LBB0_4 +; CHECK-NEXT: # %bb.1: # %bb +; CHECK-NEXT: cmpl $1, %eax +; CHECK-NEXT: je .LBB0_2 +; CHECK-NEXT: # %bb.3: # %bb5 +; CHECK-NEXT: movzwl .str.17+{{.*}}(%rip), %eax +; CHECK-NEXT: movw %ax, -{{[0-9]+}}(%rsp) +; CHECK-NEXT: movq {{.*}}(%rip), %rax +; CHECK-NEXT: jmp .LBB0_5 +; CHECK-NEXT: .LBB0_4: # %bb8 +; CHECK-NEXT: movq .str.18+{{.*}}(%rip), %rax +; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp) +; CHECK-NEXT: movq {{.*}}(%rip), %rax +; CHECK-NEXT: jmp .LBB0_5 +; CHECK-NEXT: .LBB0_2: # %bb2 +; CHECK-NEXT: movq .str.16+{{.*}}(%rip), %rax +; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp) +; CHECK-NEXT: movq {{.*}}(%rip), %rax +; CHECK-NEXT: .LBB0_5: # %bb12 +; CHECK-NEXT: movq %rax, -{{[0-9]+}}(%rsp) +; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rax +; CHECK-NEXT: movq %rax, (%rax) +; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %al +; CHECK-NEXT: movq -{{[0-9]+}}(%rsp), %rcx +; CHECK-NEXT: movzwl -{{[0-9]+}}(%rsp), %edx +; CHECK-NEXT: movl -{{[0-9]+}}(%rsp), %esi +; CHECK-NEXT: movb -{{[0-9]+}}(%rsp), %dil +; CHECK-NEXT: movb %al, (%rax) +; CHECK-NEXT: movq %rcx, 1(%rax) +; CHECK-NEXT: movw %dx, 9(%rax) +; CHECK-NEXT: movl %esi, 11(%rax) +; CHECK-NEXT: movb %dil, 15(%rax) +; CHECK-NEXT: retq bb: %tmp = alloca %0, align 16 %tmp1 = bitcast %0* %tmp to i8* diff --git a/llvm/test/CodeGen/X86/switch-jump-table.ll b/llvm/test/CodeGen/X86/switch-jump-table.ll index 4c7937078e8..1e1f7c5cef0 100644 --- a/llvm/test/CodeGen/X86/switch-jump-table.ll +++ b/llvm/test/CodeGen/X86/switch-jump-table.ll @@ -2,12 +2,14 @@ ; 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 -; An unreachable default destination is ignored and no compare and branch -; is generated for the default values. +; An unreachable default destination is replaced with the most popular case label. define void @foo(i32 %x, i32* %to) { ; CHECK-LABEL: foo: ; CHECK: movl 4(%esp), [[REG:%e[a-z]{2}]] +; CHECK: cmpl $3, [[REG]] +; CHECK: ja .LBB0_6 +; CHECK-NEXT: # %bb.1: ; CHECK-NEXT: jmpl *.LJTI0_0(,[[REG]],4) ; CHECK: movl $4 ; CHECK: retl @@ -43,12 +45,10 @@ default: ; The jump table has four entries. ; CHECK-LABEL: .LJTI0_0: -; CHECK-NEXT: .long .LBB0_1 ; CHECK-NEXT: .long .LBB0_2 ; CHECK-NEXT: .long .LBB0_3 ; CHECK-NEXT: .long .LBB0_4 ; CHECK-NEXT: .long .LBB0_5 -; CHECK-NEXT: .long .LBB0_5 } ; Check if branch probabilities are correctly assigned to the jump table. |
