Implementation of 16-bit microMIPS instructions MFHI and MFLO.

Differential Revision: http://llvm-reviews.chandlerc.com/D3141


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205532 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Mips/MicroMipsInstrFormats.td

@@ -62,6 +62,16 @@ class JALR_FM_MM16<bits<5> op> {
   let Inst{4-0}   = rs;
 }
 
+class MFHILO_FM_MM16<bits<5> funct> {
+  bits<5> rd;
+
+  bits<16> Inst;
+
+  let Inst{15-10} = 0x11;
+  let Inst{9-5}   = funct;
+  let Inst{4-0}   = rd;
+}
+
 //===----------------------------------------------------------------------===//
 // MicroMIPS 32-bit Instruction Formats
 //===----------------------------------------------------------------------===//

lib/Target/Mips/MicroMipsInstrInfo.td

@@ -70,6 +70,13 @@ class LoadMM<string opstr, DAGOperand RO, SDPatternOperator OpNode = null_frag,
   let mayLoad = 1;
 }
 
+class MoveFromHILOMM<string opstr, RegisterOperand RO, Register UseReg> :
+      MicroMipsInst16<(outs RO:$rd), (ins), !strconcat(opstr, "\t$rd"),
+  [], II_MFHI_MFLO, FrmR> {
+  let Uses = [UseReg];
+  let hasSideEffects = 0;
+}
+
 class MoveMM16<string opstr, RegisterOperand RO, bit isComm = 0,
                InstrItinClass Itin = NoItinerary> :
   MicroMipsInst16<(outs RO:$rd), (ins RO:$rs),
@@ -87,6 +94,8 @@ class JumpLinkRegMM16<string opstr, RegisterOperand RO> :
   let Defs = [RA];
 }
 
+def MFHI16_MM : MoveFromHILOMM<"mfhi", GPR32Opnd, AC0>, MFHILO_FM_MM16<0x10>;
+def MFLO16_MM : MoveFromHILOMM<"mflo", GPR32Opnd, AC0>, MFHILO_FM_MM16<0x12>;
 def MOVE16_MM : MoveMM16<"move", GPR32Opnd>, MOVE_FM_MM16<0x03>;
 def JALR16_MM : JumpLinkRegMM16<"jalr", GPR32Opnd>, JALR_FM_MM16<0x0e>;
 

lib/Target/Mips/MipsInstrInfo.td

@@ -1102,8 +1102,10 @@ def UDIV  : MMRel, Div<"divu", II_DIVU, GPR32Opnd, [HI0, LO0]>,
 
 def MTHI : MMRel, MoveToLOHI<"mthi", GPR32Opnd, [HI0]>, MTLO_FM<0x11>;
 def MTLO : MMRel, MoveToLOHI<"mtlo", GPR32Opnd, [LO0]>, MTLO_FM<0x13>;
+let Predicates = [NotInMicroMips] in {
 def MFHI : MMRel, MoveFromLOHI<"mfhi", GPR32Opnd, AC0>, MFLO_FM<0x10>;
 def MFLO : MMRel, MoveFromLOHI<"mflo", GPR32Opnd, AC0>, MFLO_FM<0x12>;
+}
 
 /// Sign Ext In Register Instructions.
 def SEB : MMRel, SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>, SEB_FM<0x10, 0x20>;

lib/Target/Mips/MipsSEInstrInfo.cpp

@@ -96,11 +96,13 @@ void MipsSEInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
       Opc = Mips::CFC1;
     else if (Mips::FGR32RegClass.contains(SrcReg))
       Opc = Mips::MFC1;
-    else if (Mips::HI32RegClass.contains(SrcReg))
+    else if (Mips::HI32RegClass.contains(SrcReg)) {
-      Opc = Mips::MFHI, SrcReg = 0;
+      Opc = isMicroMips ? Mips::MFHI16_MM : Mips::MFHI;
-    else if (Mips::LO32RegClass.contains(SrcReg))
+      SrcReg = 0;
-      Opc = Mips::MFLO, SrcReg = 0;
+    } else if (Mips::LO32RegClass.contains(SrcReg)) {
-    else if (Mips::HI32DSPRegClass.contains(SrcReg))
+      Opc = isMicroMips ? Mips::MFLO16_MM : Mips::MFLO;
+      SrcReg = 0;
+    } else if (Mips::HI32DSPRegClass.contains(SrcReg))
       Opc = Mips::MFHI_DSP;
     else if (Mips::LO32DSPRegClass.contains(SrcReg))
       Opc = Mips::MFLO_DSP;
@@ -263,6 +265,8 @@ loadRegFromStack(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
 
 bool MipsSEInstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
   MachineBasicBlock &MBB = *MI->getParent();
+  bool isMicroMips = TM.getSubtarget<MipsSubtarget>().inMicroMipsMode();
+  unsigned Opc;
 
   switch(MI->getDesc().getOpcode()) {
   default:
@@ -271,10 +275,12 @@ bool MipsSEInstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
     expandRetRA(MBB, MI, Mips::RET);
     break;
   case Mips::PseudoMFHI:
-    expandPseudoMFHiLo(MBB, MI, Mips::MFHI);
+    Opc = isMicroMips ? Mips::MFHI16_MM : Mips::MFHI;
+    expandPseudoMFHiLo(MBB, MI, Opc);
     break;
   case Mips::PseudoMFLO:
-    expandPseudoMFHiLo(MBB, MI, Mips::MFLO);
+    Opc = isMicroMips ? Mips::MFLO16_MM : Mips::MFLO;
+    expandPseudoMFHiLo(MBB, MI, Opc);
     break;
   case Mips::PseudoMFHI64:
     expandPseudoMFHiLo(MBB, MI, Mips::MFHI64);

test/MC/Mips/micromips-16-bit-instructions.s

@@ -9,13 +9,19 @@
 #------------------------------------------------------------------------------
 # Little endian
 #------------------------------------------------------------------------------
+# CHECK-EL: mfhi    $9              # encoding: [0x09,0x46]
+# CHECK-EL: mflo    $9              # encoding: [0x49,0x46]
 # CHECK-EL: move    $25, $1         # encoding: [0x21,0x0f]
 # CHECK-EL: jalr    $9              # encoding: [0xc9,0x45]
 #------------------------------------------------------------------------------
 # Big endian
 #------------------------------------------------------------------------------
+# CHECK-EB: mfhi    $9              # encoding: [0x46,0x09]
+# CHECK-EB: mflo    $9              # encoding: [0x46,0x49]
 # CHECK-EB: move    $25, $1         # encoding: [0x0f,0x21]
 # CHECK-EB: jalr    $9              # encoding: [0x45,0xc9]
 
+    mfhi    $9
+    mflo    $9
     move    $25, $1
     jalr    $9