[mips] Use MFHC1 when it is available (MIPS32r2 and later) for both FP32 and FP64 moves

Summary:
This is similar to r210771 which did the same thing for MTHC1.

Also corrected MTHC1_D32 and MTHC1_D64 which used AFGR64 and FGR64 on the
wrong definitions.

Differential Revision: http://reviews.llvm.org/D4483

llvm-svn: 212936

3 files changed, 13 insertions, 25 deletions

diff --git a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
index 902b87759dc..f35a8deefcf 100644
--- a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
+++ b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -142,11 +142,6 @@ static DecodeStatus DecodeFGR32RegisterClass(MCInst &Inst,
                                              uint64_t Address,
                                              const void *Decoder);
 
-static DecodeStatus DecodeFGRH32RegisterClass(MCInst &Inst,
-                                              unsigned RegNo,
-                                              uint64_t Address,
-                                              const void *Decoder);
-
 static DecodeStatus DecodeCCRRegisterClass(MCInst &Inst,
                                            unsigned RegNo,
                                            uint64_t Address,
@@ -914,18 +909,6 @@ static DecodeStatus DecodeFGR32RegisterClass(MCInst &Inst,
   return MCDisassembler::Success;
 }
 
-static DecodeStatus DecodeFGRH32RegisterClass(MCInst &Inst,
-                                              unsigned RegNo,
-                                              uint64_t Address,
-                                              const void *Decoder) {
-  if (RegNo > 31)
-    return MCDisassembler::Fail;
-
-  unsigned Reg = getReg(Decoder, Mips::FGRH32RegClassID, RegNo);
-  Inst.addOperand(MCOperand::CreateReg(Reg));
-  return MCDisassembler::Success;
-}
-
 static DecodeStatus DecodeCCRRegisterClass(MCInst &Inst,
                                            unsigned RegNo,
                                            uint64_t Address,
diff --git a/llvm/lib/Target/Mips/MipsInstrFPU.td b/llvm/lib/Target/Mips/MipsInstrFPU.td
index 2260d53567f..29d8e30be48 100644
--- a/llvm/lib/Target/Mips/MipsInstrFPU.td
+++ b/llvm/lib/Target/Mips/MipsInstrFPU.td
@@ -362,11 +362,15 @@ def MFC1 : MMRel, MFC1_FT<"mfc1", GPR32Opnd, FGR32Opnd, II_MFC1,
                           bitconvert>, MFC1_FM<0>;
 def MTC1 : MMRel, MTC1_FT<"mtc1", FGR32Opnd, GPR32Opnd, II_MTC1,
                           bitconvert>, MFC1_FM<4>;
-def MFHC1 : MMRel, MFC1_FT<"mfhc1", GPR32Opnd, FGRH32Opnd, II_MFHC1>,
-            MFC1_FM<3>, ISA_MIPS32R2;
-def MTHC1_D32 : MMRel, MTC1_64_FT<"mthc1", FGR64Opnd, GPR32Opnd, II_MTHC1>,
+def MFHC1_D32 : MMRel, MFC1_FT<"mfhc1", GPR32Opnd, AFGR64Opnd, II_MFHC1>,
+                MFC1_FM<3>, ISA_MIPS32R2, AdditionalRequires<[NotFP64bit]>;
+def MFHC1_D64 : MFC1_FT<"mfhc1", GPR32Opnd, FGR64Opnd, II_MFHC1>,
+                MFC1_FM<3>, ISA_MIPS32R2, AdditionalRequires<[IsFP64bit]> {
+  let DecoderNamespace = "Mips64";
+}
+def MTHC1_D32 : MMRel, MTC1_64_FT<"mthc1", AFGR64Opnd, GPR32Opnd, II_MTHC1>,
                 MFC1_FM<7>, ISA_MIPS32R2, AdditionalRequires<[NotFP64bit]>;
-def MTHC1_D64 : MTC1_64_FT<"mthc1", AFGR64Opnd, GPR32Opnd, II_MTHC1>,
+def MTHC1_D64 : MTC1_64_FT<"mthc1", FGR64Opnd, GPR32Opnd, II_MTHC1>,
                 MFC1_FM<7>, ISA_MIPS32R2, AdditionalRequires<[IsFP64bit]> {
   let DecoderNamespace = "Mips64";
 }
diff --git a/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp b/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
index aad401857c3..d242659d076 100644
--- a/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
@@ -521,8 +521,9 @@ void MipsSEInstrInfo::expandExtractElementF64(MachineBasicBlock &MBB,
   unsigned SubIdx = N ? Mips::sub_hi : Mips::sub_lo;
   unsigned SubReg = getRegisterInfo().getSubReg(SrcReg, SubIdx);
 
-  if (SubIdx == Mips::sub_hi && FP64) {
-    // FIXME: The .addReg(SrcReg, RegState::Implicit) is a white lie used to
+  if (SubIdx == Mips::sub_hi && TM.getSubtarget<MipsSubtarget>().hasMTHC1()) {
+    // FIXME: Strictly speaking MFHC1 only reads the top 32-bits however, we
+    //        claim to read the whole 64-bits as part of a white lie used to
     //        temporarily work around a widespread bug in the -mfp64 support.
     //        The problem is that none of the 32-bit fpu ops mention the fact
     //        that they clobber the upper 32-bits of the 64-bit FPR. Fixing that
@@ -533,8 +534,8 @@ void MipsSEInstrInfo::expandExtractElementF64(MachineBasicBlock &MBB,
     //        We therefore pretend that it reads the bottom 32-bits to
     //        artificially create a dependency and prevent the scheduler
     //        changing the behaviour of the code.
-    BuildMI(MBB, I, dl, get(Mips::MFHC1), DstReg).addReg(SubReg).addReg(
-        SrcReg, RegState::Implicit);
+    BuildMI(MBB, I, dl, get(FP64 ? Mips::MFHC1_D64 : Mips::MFHC1_D32), DstReg)
+        .addReg(SrcReg);
   } else
     BuildMI(MBB, I, dl, get(Mips::MFC1), DstReg).addReg(SubReg);
 }