From 2b7b2f373b7275330da97feaacaeb76342470072 Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Thu, 8 Aug 2013 04:31:34 +0000 Subject: PPC: Map frin to round() not nearbyint() and rint() Making use of the recently-added ISD::FROUND, which allows for custom lowering of round(), the PPC backend will now map frin to round(). Previously, we had been using frin to lower nearbyint() (and rint() via some custom lowering to handle the extra fenv flags requirements), but only in fast-math mode because frin does not tie-to-even. Several users had complained about this behavior, and this new mapping of frin to round is certainly more appropriate (and does not require fast-math mode). In effect, this reverts r178362 (and part of r178337, replacing the nearbyint mapping with the round mapping). llvm-svn: 187960 --- llvm/lib/Target/PowerPC/PPCISelLowering.cpp | 58 +---------------------------- 1 file changed, 2 insertions(+), 56 deletions(-) (limited to 'llvm/lib/Target/PowerPC/PPCISelLowering.cpp') diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp index 664dd12573a..886def1b457 100644 --- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp +++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp @@ -156,21 +156,12 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM) setOperationAction(ISD::FFLOOR, MVT::f64, Legal); setOperationAction(ISD::FCEIL, MVT::f64, Legal); setOperationAction(ISD::FTRUNC, MVT::f64, Legal); + setOperationAction(ISD::FROUND, MVT::f64, Legal); setOperationAction(ISD::FFLOOR, MVT::f32, Legal); setOperationAction(ISD::FCEIL, MVT::f32, Legal); setOperationAction(ISD::FTRUNC, MVT::f32, Legal); - - // frin does not implement "ties to even." Thus, this is safe only in - // fast-math mode. - if (TM.Options.UnsafeFPMath) { - setOperationAction(ISD::FNEARBYINT, MVT::f64, Legal); - setOperationAction(ISD::FNEARBYINT, MVT::f32, Legal); - - // These need to set FE_INEXACT, and use a custom inserter. - setOperationAction(ISD::FRINT, MVT::f64, Legal); - setOperationAction(ISD::FRINT, MVT::f32, Legal); - } + setOperationAction(ISD::FROUND, MVT::f32, Legal); } // PowerPC does not have BSWAP, CTPOP or CTTZ @@ -6676,51 +6667,6 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI, // Restore FPSCR value. BuildMI(*BB, MI, dl, TII->get(PPC::MTFSF)).addImm(1).addReg(MFFSReg); - } else if (MI->getOpcode() == PPC::FRINDrint || - MI->getOpcode() == PPC::FRINSrint) { - bool isf32 = MI->getOpcode() == PPC::FRINSrint; - unsigned Dest = MI->getOperand(0).getReg(); - unsigned Src = MI->getOperand(1).getReg(); - DebugLoc dl = MI->getDebugLoc(); - - MachineRegisterInfo &RegInfo = F->getRegInfo(); - unsigned CRReg = RegInfo.createVirtualRegister(&PPC::CRRCRegClass); - - // Perform the rounding. - BuildMI(*BB, MI, dl, TII->get(isf32 ? PPC::FRINS : PPC::FRIND), Dest) - .addReg(Src); - - // Compare the results. - BuildMI(*BB, MI, dl, TII->get(isf32 ? PPC::FCMPUS : PPC::FCMPUD), CRReg) - .addReg(Dest).addReg(Src); - - // If the results were not equal, then set the FPSCR XX bit. - MachineBasicBlock *midMBB = F->CreateMachineBasicBlock(LLVM_BB); - MachineBasicBlock *exitMBB = F->CreateMachineBasicBlock(LLVM_BB); - F->insert(It, midMBB); - F->insert(It, exitMBB); - exitMBB->splice(exitMBB->begin(), BB, - llvm::next(MachineBasicBlock::iterator(MI)), - BB->end()); - exitMBB->transferSuccessorsAndUpdatePHIs(BB); - - BuildMI(*BB, MI, dl, TII->get(PPC::BCC)) - .addImm(PPC::PRED_EQ).addReg(CRReg).addMBB(exitMBB); - - BB->addSuccessor(midMBB); - BB->addSuccessor(exitMBB); - - BB = midMBB; - - // Set the FPSCR XX bit (FE_INEXACT). Note that we cannot just set - // the FI bit here because that will not automatically set XX also, - // and XX is what libm interprets as the FE_INEXACT flag. - BuildMI(BB, dl, TII->get(PPC::MTFSB1)).addImm(/* 38 - 32 = */ 6); - BuildMI(BB, dl, TII->get(PPC::B)).addMBB(exitMBB); - - BB->addSuccessor(exitMBB); - - BB = exitMBB; } else { llvm_unreachable("Unexpected instr type to insert"); } -- cgit v1.2.3