[mips] Absolute value macro expansion

Author: obucina
Reviewers: dsanders
Differential Revision: http://reviews.llvm.org/D16323

llvm-svn: 259202

2 files changed, 25 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index a13d1d794ab..192b3444936 100644
--- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -233,6 +233,9 @@ class MipsAsmParser : public MCTargetAsmParser {
   bool expandDRotationImm(MCInst &Inst, SMLoc IDLoc,
                           SmallVectorImpl<MCInst> &Instructions);
 
+  bool expandAbs(MCInst &Inst, SMLoc IDLoc,
+                 SmallVectorImpl<MCInst> &Instructions);
+
   void createNop(bool hasShortDelaySlot, SMLoc IDLoc,
                  SmallVectorImpl<MCInst> &Instructions);
 
@@ -2087,6 +2090,9 @@ MipsAsmParser::tryExpandInstruction(MCInst &Inst, SMLoc IDLoc,
   case Mips::DRORImm:
     return expandDRotationImm(Inst, IDLoc, Instructions) ? MER_Fail
                                                          : MER_Success;
+  case Mips::ABSMacro:
+    return expandAbs(Inst, IDLoc, Instructions) ? MER_Fail
+                                                : MER_Success;
   }
 }
 
@@ -3531,6 +3537,22 @@ bool MipsAsmParser::expandDRotationImm(MCInst &Inst, SMLoc IDLoc,
   return true;
 }
 
+bool MipsAsmParser::expandAbs(MCInst &Inst, SMLoc IDLoc,
+                              SmallVectorImpl<MCInst> &Instructions) {
+
+  unsigned FirstRegOp = Inst.getOperand(0).getReg();
+  unsigned SecondRegOp = Inst.getOperand(1).getReg();
+
+  emitRI(Mips::BGEZ, SecondRegOp, 8, IDLoc, Instructions);
+  if (FirstRegOp != SecondRegOp)
+    emitRRR(Mips::ADDu, FirstRegOp, SecondRegOp, Mips::ZERO, IDLoc, Instructions);
+  else
+    createNop(false, IDLoc, Instructions);
+  emitRRR(Mips::SUB, FirstRegOp, Mips::ZERO, SecondRegOp, IDLoc, Instructions);
+
+  return false;
+}
+
 void MipsAsmParser::createNop(bool hasShortDelaySlot, SMLoc IDLoc,
                               SmallVectorImpl<MCInst> &Instructions) {
   if (hasShortDelaySlot)
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.td b/llvm/lib/Target/Mips/MipsInstrInfo.td
index ffda491f0c8..c5a314fe2d8 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.td
@@ -1808,6 +1808,9 @@ def : MipsInstAlias<"dror $rd, $rs",
 def : MipsInstAlias<"dror $rd, $imm",
                     (DRORImm GPR32Opnd:$rd, GPR32Opnd:$rd, simm16:$imm), 0>, ISA_MIPS64;
 
+def ABSMacro : MipsAsmPseudoInst<(outs GPR32Opnd:$rd), (ins GPR32Opnd:$rs),
+                                 "abs\t$rd, $rs">;
+
 //===----------------------------------------------------------------------===//
 // Instruction aliases
 //===----------------------------------------------------------------------===//