[mips][mips64r6] c.cond.fmt, mov[fntz], and mov[fntz].[ds] are not available on MIPS32r6/MIPS64r6

Summary:
c.cond.fmt has been replaced by cmp.cond.fmt. Where c.cond.fmt wrote to
dedicated condition registers, cmp.cond.fmt writes 1 or 0 to normal FGR's
(like the GPR comparisons).

mov[fntz] have been replaced by seleqz and selnez. These instructions
conditionally zero a register based on a bool in a GPR. The results can
then be or'd together to act as a select without, for example, requiring a third
register read port.

mov[fntz].[ds] have been replaced with sel.[ds]

MIPS64r6 currently generates unnecessary sign-extensions for most selects.
This is because the result of a SETCC is currently an i32. Bits 32-63 are
undefined in i32 and the behaviour of seleqz/selnez would otherwise depend
on undefined bits. Later, we will fix this by making the result of SETCC an
i64 on MIPS64 targets.

Depends on D3958

Reviewers: jkolek, vmedic, zoran.jovanovic

Reviewed By: vmedic, zoran.jovanovic

Differential Revision: http://reviews.llvm.org/D4003

llvm-svn: 210777

1 files changed, 30 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
index 54df55cbc87..0389d848ade 100644
--- a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
+++ b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -67,6 +67,8 @@ public:
     return STI.getFeatureBits() & Mips::FeatureMips32r6;
   }
 
+  bool isGP64() const { return STI.getFeatureBits() & Mips::FeatureGP64Bit; }
+
   /// getInstruction - See MCDisassembler.
   DecodeStatus getInstruction(MCInst &instr,
                               uint64_t &size,
@@ -149,6 +151,10 @@ static DecodeStatus DecodeFCCRegisterClass(MCInst &Inst,
                                            uint64_t Address,
                                            const void *Decoder);
 
+static DecodeStatus DecodeFGRCCRegisterClass(MCInst &Inst, unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
 static DecodeStatus DecodeHWRegsRegisterClass(MCInst &Inst,
                                               unsigned Insn,
                                               uint64_t Address,
@@ -727,6 +733,7 @@ MipsDisassembler::getInstruction(MCInst &instr,
     return MCDisassembler::Fail;
 
   if (IsMicroMips) {
+    DEBUG(dbgs() << "Trying MicroMips32 table (32-bit opcodes):\n");
     // Calling the auto-generated decoder function.
     Result = decodeInstruction(DecoderTableMicroMips32, instr, Insn, Address,
                                this, STI);
@@ -737,7 +744,18 @@ MipsDisassembler::getInstruction(MCInst &instr,
     return MCDisassembler::Fail;
   }
 
+  if (isMips32r6() && isGP64()) {
+    DEBUG(dbgs() << "Trying Mips32r6_64r6 (GPR64) table (32-bit opcodes):\n");
+    Result = decodeInstruction(DecoderTableMips32r6_64r6_GP6432, instr, Insn,
+                               Address, this, STI);
+    if (Result != MCDisassembler::Fail) {
+      Size = 4;
+      return Result;
+    }
+  }
+
   if (isMips32r6()) {
+    DEBUG(dbgs() << "Trying Mips32r6_64r6 table (32-bit opcodes):\n");
     Result = decodeInstruction(DecoderTableMips32r6_64r632, instr, Insn,
                                Address, this, STI);
     if (Result != MCDisassembler::Fail) {
@@ -746,6 +764,7 @@ MipsDisassembler::getInstruction(MCInst &instr,
     }
   }
 
+  DEBUG(dbgs() << "Trying Mips table (32-bit opcodes):\n");
   // Calling the auto-generated decoder function.
   Result = decodeInstruction(DecoderTableMips32, instr, Insn, Address,
                              this, STI);
@@ -897,6 +916,17 @@ static DecodeStatus DecodeFCCRegisterClass(MCInst &Inst,
   return MCDisassembler::Success;
 }
 
+static DecodeStatus DecodeFGRCCRegisterClass(MCInst &Inst, unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::FGRCCRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
 static DecodeStatus DecodeMem(MCInst &Inst,
                               unsigned Insn,
                               uint64_t Address,