[mips] MIPS64R6 compact branch support

MIPS64R6 compact branch support. As the MIPS LLVM backend uses distinct
MachineInstrs for certain 32 and 64 bit instructions (e.g. BEQ & BEQ64) that
map to the same instruction, extend compact branch support for the
corresponding 64bit branches.

Reviewers: dsanders

Differential Revision: https://reviews.llvm.org/D20164

llvm-svn: 276739
diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index b51d020..6b613fb 100644
--- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -3720,7 +3720,14 @@
   case Mips::BLTZC:
   case Mips::BEQZC:
   case Mips::BNEZC:
-    if (Inst.getOperand(0).getReg() == Mips::ZERO)
+  case Mips::BLEZC64:
+  case Mips::BGEZC64:
+  case Mips::BGTZC64:
+  case Mips::BLTZC64:
+  case Mips::BEQZC64:
+  case Mips::BNEZC64:
+    if (Inst.getOperand(0).getReg() == Mips::ZERO ||
+        Inst.getOperand(0).getReg() == Mips::ZERO_64)
       return Match_RequiresNoZeroRegister;
     return Match_Success;
   case Mips::BGEC:
@@ -3729,9 +3736,17 @@
   case Mips::BLTUC:
   case Mips::BEQC:
   case Mips::BNEC:
-    if (Inst.getOperand(0).getReg() == Mips::ZERO)
+  case Mips::BGEC64:
+  case Mips::BLTC64:
+  case Mips::BGEUC64:
+  case Mips::BLTUC64:
+  case Mips::BEQC64:
+  case Mips::BNEC64:
+    if (Inst.getOperand(0).getReg() == Mips::ZERO ||
+        Inst.getOperand(0).getReg() == Mips::ZERO_64)
       return Match_RequiresNoZeroRegister;
-    if (Inst.getOperand(1).getReg() == Mips::ZERO)
+    if (Inst.getOperand(1).getReg() == Mips::ZERO ||
+        Inst.getOperand(1).getReg() == Mips::ZERO_64)
       return Match_RequiresNoZeroRegister;
     if (Inst.getOperand(0).getReg() == Inst.getOperand(1).getReg())
       return Match_RequiresDifferentOperands;
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
index 401c7d4..c15c8a92 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
@@ -129,7 +129,8 @@
   unsigned Reg0 =  Ctx.getRegisterInfo()->getEncodingValue(RegOp0);
   unsigned Reg1 =  Ctx.getRegisterInfo()->getEncodingValue(RegOp1);
 
-  if (Inst.getOpcode() == Mips::BNEC || Inst.getOpcode() == Mips::BEQC) {
+  if (Inst.getOpcode() == Mips::BNEC || Inst.getOpcode() == Mips::BEQC ||
+      Inst.getOpcode() == Mips::BNEC64 || Inst.getOpcode() == Mips::BEQC64) {
     assert(Reg0 != Reg1 && "Instruction has bad operands ($rs == $rt)!");
     if (Reg0 < Reg1)
       return;
@@ -141,7 +142,7 @@
     if (Reg1 >= Reg0)
       return;
   } else
-   llvm_unreachable("Cannot rewrite unknown branch!");
+    llvm_unreachable("Cannot rewrite unknown branch!");
 
   Inst.getOperand(0).setReg(RegOp1);
   Inst.getOperand(1).setReg(RegOp0);
@@ -210,6 +211,8 @@
   // Compact branches, enforce encoding restrictions.
   case Mips::BEQC:
   case Mips::BNEC:
+  case Mips::BEQC64:
+  case Mips::BNEC64:
   case Mips::BOVC:
   case Mips::BOVC_MMR6:
   case Mips::BNVC:
diff --git a/llvm/lib/Target/Mips/Mips64r6InstrInfo.td b/llvm/lib/Target/Mips/Mips64r6InstrInfo.td
index 64effbe..d48b16e 100644
--- a/llvm/lib/Target/Mips/Mips64r6InstrInfo.td
+++ b/llvm/lib/Target/Mips/Mips64r6InstrInfo.td
@@ -76,6 +76,19 @@
 class SELEQZ64_DESC : SELEQNE_Z_DESC_BASE<"seleqz", GPR64Opnd>;
 class SELNEZ64_DESC : SELEQNE_Z_DESC_BASE<"selnez", GPR64Opnd>;
 
+class BGEC64_DESC : CMP_BC_DESC_BASE<"bgec", brtarget, GPR64Opnd>;
+class BGEUC64_DESC : CMP_BC_DESC_BASE<"bgeuc", brtarget, GPR64Opnd>;
+class BEQC64_DESC : CMP_BC_DESC_BASE<"beqc", brtarget, GPR64Opnd>;
+class BNEC64_DESC : CMP_BC_DESC_BASE<"bnec", brtarget, GPR64Opnd>;
+class BLTC64_DESC : CMP_BC_DESC_BASE<"bltc", brtarget, GPR64Opnd>;
+class BLTUC64_DESC : CMP_BC_DESC_BASE<"bltuc", brtarget, GPR64Opnd>;
+class BLTZC64_DESC : CMP_CBR_RT_Z_DESC_BASE<"bltzc", brtarget, GPR64Opnd>;
+class BGEZC64_DESC : CMP_CBR_RT_Z_DESC_BASE<"bgezc", brtarget, GPR64Opnd>;
+class BLEZC64_DESC : CMP_CBR_RT_Z_DESC_BASE<"blezc", brtarget, GPR64Opnd>;
+class BGTZC64_DESC : CMP_CBR_RT_Z_DESC_BASE<"bgtzc", brtarget, GPR64Opnd>;
+class BEQZC64_DESC : CMP_CBR_EQNE_Z_DESC_BASE<"beqzc", brtarget21, GPR64Opnd>;
+class BNEZC64_DESC : CMP_CBR_EQNE_Z_DESC_BASE<"bnezc", brtarget21, GPR64Opnd>;
+
 class JIALC64_DESC : JMP_IDX_COMPACT_DESC_BASE<"jialc", calloffset16,
                                              GPR64Opnd> {
   bit isCall = 1;
@@ -130,10 +143,28 @@
   def LL64_R6 : LL_R6_ENC, LL64_R6_DESC, PTR_64, ISA_MIPS64R6;
   def SC64_R6 : SC_R6_ENC, SC64_R6_DESC, PTR_64, ISA_MIPS64R6;
 }
-let isCodeGenOnly = 1 in {
-def JIALC64 : JIALC_ENC, JIALC64_DESC, ISA_MIPS64R6;
-def JIC64 : JIC_ENC, JIC64_DESC, ISA_MIPS64R6;
+
+let DecoderNamespace = "Mips32r6_64r6_GP64" in {
+// Jump and Branch Instructions
+def JIALC64 : JIALC_ENC, JIALC64_DESC, ISA_MIPS64R6, GPR_64;
+def JIC64 : JIC_ENC, JIC64_DESC, ISA_MIPS64R6, GPR_64;
+
+def BEQC64 : BEQC_ENC, BEQC64_DESC, ISA_MIPS64R6, GPR_64;
+def BEQZC64 : BEQZC_ENC, BEQZC64_DESC, ISA_MIPS64R6, GPR_64;
+def BGEC64 : BGEC_ENC, BGEC64_DESC, ISA_MIPS64R6, GPR_64;
+def BGEUC64 : BGEUC_ENC, BGEUC64_DESC, ISA_MIPS64R6, GPR_64;
+def BGTZC64 : BGTZC_ENC, BGTZC64_DESC, ISA_MIPS64R6, GPR_64;
+def BLEZC64 : BLEZC_ENC, BLEZC64_DESC, ISA_MIPS64R6, GPR_64;
+def BLTC64 : BLTC_ENC, BLTC64_DESC, ISA_MIPS64R6, GPR_64;
+def BLTUC64 : BLTUC_ENC, BLTUC64_DESC, ISA_MIPS64R6, GPR_64;
+def BNEC64 : BNEC_ENC, BNEC64_DESC, ISA_MIPS64R6, GPR_64;
+def BNEZC64 : BNEZC_ENC, BNEZC64_DESC, ISA_MIPS64R6, GPR_64;
 }
+let DecoderNamespace = "Mips32r6_64r6_BranchZero" in {
+def BLTZC64 : BLTZC_ENC, BLTZC64_DESC, ISA_MIPS64R6, GPR_64;
+def BGEZC64 : BGEZC_ENC, BGEZC64_DESC, ISA_MIPS64R6, GPR_64;
+}
+
 //===----------------------------------------------------------------------===//
 //
 // Instruction Aliases
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.cpp b/llvm/lib/Target/Mips/MipsInstrInfo.cpp
index 9bbdd7d..de0ceaf 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.cpp
@@ -341,6 +341,22 @@
       return Mips::BLTUC;
     case Mips::BLTZ:
       return Mips::BLTZC;
+    case Mips::BEQ64:
+      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
+        return 0;
+      return Mips::BEQC64;
+    case Mips::BNE64:
+      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
+        return 0;
+      return Mips::BNEC64;
+    case Mips::BGTZ64:
+      return Mips::BGTZC64;
+    case Mips::BGEZ64:
+      return Mips::BGEZC64;
+    case Mips::BLTZ64:
+      return Mips::BLTZC64;
+    case Mips::BLEZ64:
+      return Mips::BLEZC64;
     // For MIPSR6, the instruction 'jic' can be used for these cases. Some
     // tools will accept 'jrc reg' as an alias for 'jic 0, $reg'.
     case Mips::JR:
@@ -403,7 +419,7 @@
                                   MachineBasicBlock::iterator I) const {
   MachineInstrBuilder MIB;
 
-  // Certain branches have two forms: e.g beq $1, $zero, dst vs beqz $1, dest
+  // Certain branches have two forms: e.g beq $1, $zero, dest vs beqz $1, dest
   // Pick the zero form of the branch for readable assembly and for greater
   // branch distance in non-microMIPS mode.
   // FIXME: Certain atomic sequences on mips64 generate 32bit references to
@@ -429,6 +445,12 @@
     case Mips::BLTC:
       NewOpc = Mips::BLTZC;
       break;
+    case Mips::BEQC64:
+      NewOpc = Mips::BEQZC64;
+      break;
+    case Mips::BNEC64:
+      NewOpc = Mips::BNEZC64;
+      break;
     }
   }
 
diff --git a/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp b/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
index 4caa3e0..ea703d0 100644
--- a/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
@@ -433,6 +433,18 @@
   case Mips::BGEZC:  return Mips::BLTZC;
   case Mips::BLTZC:  return Mips::BGEZC;
   case Mips::BLEZC:  return Mips::BGTZC;
+  case Mips::BEQZC64:  return Mips::BNEZC64;
+  case Mips::BNEZC64:  return Mips::BEQZC64;
+  case Mips::BEQC64:   return Mips::BNEC64;
+  case Mips::BNEC64:   return Mips::BEQC64;
+  case Mips::BGEC64:   return Mips::BLTC64;
+  case Mips::BGEUC64:  return Mips::BLTUC64;
+  case Mips::BLTC64:   return Mips::BGEC64;
+  case Mips::BLTUC64:  return Mips::BGEUC64;
+  case Mips::BGTZC64:  return Mips::BLEZC64;
+  case Mips::BGEZC64:  return Mips::BLTZC64;
+  case Mips::BLTZC64:  return Mips::BGEZC64;
+  case Mips::BLEZC64:  return Mips::BGTZC64;
   }
 }
 
@@ -518,8 +530,12 @@
           Opc == Mips::BNEC   || Opc == Mips::BLTC   || Opc == Mips::BGEC   ||
           Opc == Mips::BLTUC  || Opc == Mips::BGEUC  || Opc == Mips::BGTZC  ||
           Opc == Mips::BLEZC  || Opc == Mips::BGEZC  || Opc == Mips::BLTZC  ||
-          Opc == Mips::BEQZC  || Opc == Mips::BNEZC  ||
-          Opc == Mips::BC) ? Opc : 0;
+          Opc == Mips::BEQZC  || Opc == Mips::BNEZC  || Opc == Mips::BEQZC64 ||
+          Opc == Mips::BNEZC64 || Opc == Mips::BEQC64 || Opc == Mips::BNEC64 ||
+          Opc == Mips::BGEC64 || Opc == Mips::BGEUC64 || Opc == Mips::BLTC64 ||
+          Opc == Mips::BLTUC64 || Opc == Mips::BGTZC64 ||
+          Opc == Mips::BGEZC64 || Opc == Mips::BLTZC64 ||
+          Opc == Mips::BLEZC64 || Opc == Mips::BC) ? Opc : 0;
 }
 
 void MipsSEInstrInfo::expandRetRA(MachineBasicBlock &MBB,