[mips] Fix instruction selection pattern for sint_to_fp node to avoid emitting an
invalid instruction sequence.
Rather than emitting an int-to-FP move instruction and an int-to-FP conversion
instruction during instruction selection, we emit a pseudo instruction which gets
expanded post-RA. Without this change, register allocation can possibly insert a
floating point register move instruction between the two instructions, which is not
valid according to the ISA manual.
mtc1 $f4, $4 # int-to-fp move instruction.
mov.s $f2, $f4 # move contents of $f4 to $f2.
cvt.s.w $f0, $f2 # int-to-fp conversion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182042 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsSEInstrInfo.cpp b/lib/Target/Mips/MipsSEInstrInfo.cpp
index 12ed1bc..7a8ed7a 100644
--- a/lib/Target/Mips/MipsSEInstrInfo.cpp
+++ b/lib/Target/Mips/MipsSEInstrInfo.cpp
@@ -253,6 +253,21 @@
case Mips::RetRA:
expandRetRA(MBB, MI, Mips::RET);
break;
+ case Mips::PseudoCVT_S_W:
+ expandCvtFPInt(MBB, MI, Mips::CVT_S_W, Mips::MTC1, false, false, false);
+ break;
+ case Mips::PseudoCVT_D32_W:
+ expandCvtFPInt(MBB, MI, Mips::CVT_D32_W, Mips::MTC1, true, false, false);
+ break;
+ case Mips::PseudoCVT_S_L:
+ expandCvtFPInt(MBB, MI, Mips::CVT_S_L, Mips::DMTC1, false, true, true);
+ break;
+ case Mips::PseudoCVT_D64_W:
+ expandCvtFPInt(MBB, MI, Mips::CVT_D64_W, Mips::MTC1, true, false, true);
+ break;
+ case Mips::PseudoCVT_D64_L:
+ expandCvtFPInt(MBB, MI, Mips::CVT_D64_L, Mips::DMTC1, false, false, true);
+ break;
case Mips::BuildPairF64:
expandBuildPairF64(MBB, MI);
break;
@@ -374,6 +389,28 @@
BuildMI(MBB, I, I->getDebugLoc(), get(Opc)).addReg(Mips::RA);
}
+void MipsSEInstrInfo::expandCvtFPInt(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I,
+ unsigned CvtOpc, unsigned MovOpc,
+ bool DstIsLarger, bool SrcIsLarger,
+ bool IsI64) const {
+ const MCInstrDesc &CvtDesc = get(CvtOpc), &MovDesc = get(MovOpc);
+ const MachineOperand &Dst = I->getOperand(0), &Src = I->getOperand(1);
+ unsigned DstReg = Dst.getReg(), SrcReg = Src.getReg(), TmpReg = DstReg;
+ unsigned KillSrc = getKillRegState(Src.isKill());
+ DebugLoc DL = I->getDebugLoc();
+ unsigned SubIdx = (IsI64 ? Mips::sub_32 : Mips::sub_fpeven);
+
+ if (DstIsLarger)
+ TmpReg = getRegisterInfo().getSubReg(DstReg, SubIdx);
+
+ if (SrcIsLarger)
+ DstReg = getRegisterInfo().getSubReg(DstReg, SubIdx);
+
+ BuildMI(MBB, I, DL, MovDesc, TmpReg).addReg(SrcReg, KillSrc);
+ BuildMI(MBB, I, DL, CvtDesc, DstReg).addReg(TmpReg, RegState::Kill);
+}
+
void MipsSEInstrInfo::expandExtractElementF64(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
unsigned DstReg = I->getOperand(0).getReg();