From 46773793cbf18fa0fa4643c91d3b6f5c5bf15dd9 Mon Sep 17 00:00:00 2001 From: Bruno Cardoso Lopes Date: Tue, 20 Jul 2010 08:37:04 +0000 Subject: [PATCH] Fix PR7174, a couple o Mips fixes: - Fix a typo for PIC check during jmp table lowering - Also fix the "first jump table basic block is not considered only reachable by fall through" problem, use this ad-hoc solution until I come up with something better. Patch by stetorvs@gmail.com git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108820 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp | 20 +++++++++++ lib/Target/Mips/MipsISelLowering.cpp | 2 +- test/CodeGen/Mips/2010-07-20-Switch.ll | 33 +++++++++++++++++++ 3 files changed, 54 insertions(+), 1 deletion(-) create mode 100644 test/CodeGen/Mips/2010-07-20-Switch.ll diff --git a/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp b/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp index 8ae05b75e91..6660f6b6243 100644 --- a/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp +++ b/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp @@ -18,6 +18,8 @@ #include "MipsInstrInfo.h" #include "MipsTargetMachine.h" #include "MipsMachineFunction.h" +#include "llvm/BasicBlock.h" +#include "llvm/Instructions.h" #include "llvm/CodeGen/AsmPrinter.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineConstantPool.h" @@ -75,6 +77,7 @@ namespace { } virtual void EmitFunctionBodyStart(); virtual void EmitFunctionBodyEnd(); + virtual bool isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const; static const char *getRegisterName(unsigned RegNo); virtual void EmitFunctionEntryLabel(); @@ -227,6 +230,23 @@ void MipsAsmPrinter::EmitFunctionBodyEnd() { } +/// isBlockOnlyReachableByFallthough - Return true if the basic block has +/// exactly one predecessor and the control transfer mechanism between +/// the predecessor and this block is a fall-through. +bool MipsAsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) + const { + // The predecessor has to be immediately before this block. + const MachineBasicBlock *Pred = *MBB->pred_begin(); + + // If the predecessor is a switch statement, assume a jump table + // implementation, so it is not a fall through. + if (const BasicBlock *bb = Pred->getBasicBlock()) + if (isa(bb->getTerminator())) + return false; + + return AsmPrinter::isBlockOnlyReachableByFallthrough(MBB); +} + // Print out an operand for an inline asm expression. bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, unsigned AsmVariant,const char *ExtraCode, diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp index f67572e8041..b0b99bad160 100644 --- a/lib/Target/Mips/MipsISelLowering.cpp +++ b/lib/Target/Mips/MipsISelLowering.cpp @@ -542,7 +542,7 @@ LowerJumpTable(SDValue Op, SelectionDAG &DAG) const SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT, OpFlag); - if (IsPIC) { + if (!IsPIC) { SDValue Ops[] = { JTI }; HiPart = DAG.getNode(MipsISD::Hi, dl, DAG.getVTList(MVT::i32), Ops, 1); } else // Emit Load from Global Pointer diff --git a/test/CodeGen/Mips/2010-07-20-Switch.ll b/test/CodeGen/Mips/2010-07-20-Switch.ll new file mode 100644 index 00000000000..07fc10cae18 --- /dev/null +++ b/test/CodeGen/Mips/2010-07-20-Switch.ll @@ -0,0 +1,33 @@ +; RUN: llc < %s -march=mips -relocation-model=static | FileCheck %s + +define i32 @main() nounwind readnone { +entry: + %x = alloca i32, align 4 ; [#uses=2] + volatile store i32 2, i32* %x, align 4 + %0 = volatile load i32* %x, align 4 ; [#uses=1] +; CHECK: lui $3, %hi($JTI0_0) +; CHECK: sll $2, $2, 2 +; CHECK: addiu $3, $3, %lo($JTI0_0) + switch i32 %0, label %bb4 [ + i32 0, label %bb5 + i32 1, label %bb1 + i32 2, label %bb2 + i32 3, label %bb3 + ] + +bb1: ; preds = %entry + ret i32 2 + +; CHECK: $BB0_2 +bb2: ; preds = %entry + ret i32 0 + +bb3: ; preds = %entry + ret i32 3 + +bb4: ; preds = %entry + ret i32 4 + +bb5: ; preds = %entry + ret i32 1 +}