[mips][ias] Implement macro expansion when bcc has an immediate where a register belongs.

[dsanders]

Summary

Fixes PR24915.

[vkalintiris]

LGTM.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

bool MipsAsmParser::needsExpansion(MCInst &Inst) {
   case Mips::BLTL:
   case Mips::BLEL:
   case Mips::BGEL:
   case Mips::BGTL:
   case Mips::BLTUL:
   case Mips::BLEUL:
   case Mips::BGEUL:
   case Mips::BGTUL:
+  case Mips::BLTImmMacro:
+  case Mips::BLEImmMacro:
+  case Mips::BGEImmMacro:
+  case Mips::BGTImmMacro:
+  case Mips::BLTUImmMacro:
+  case Mips::BLEUImmMacro:
+  case Mips::BGEUImmMacro:
+  case Mips::BGTUImmMacro:
+  case Mips::BLTLImmMacro:
+  case Mips::BLELImmMacro:
+  case Mips::BGELImmMacro:
+  case Mips::BGTLImmMacro:
+  case Mips::BLTULImmMacro:
+  case Mips::BLEULImmMacro:
+  case Mips::BGEULImmMacro:
+  case Mips::BGTULImmMacro:
   case Mips::SDivMacro:
   case Mips::UDivMacro:
   case Mips::DSDivMacro:
   case Mips::DUDivMacro:
   case Mips::Ulhu:
   case Mips::Ulw:
   case Mips::NORImm:
     return true;
bool MipsAsmParser::expandInstruction(MCInst &Inst, SMLoc IDLoc,
   case Mips::BLTL:
   case Mips::BLEL:
   case Mips::BGEL:
   case Mips::BGTL:
   case Mips::BLTUL:
   case Mips::BLEUL:
   case Mips::BGEUL:
   case Mips::BGTUL:
+  case Mips::BLTImmMacro:
+  case Mips::BLEImmMacro:
+  case Mips::BGEImmMacro:
+  case Mips::BGTImmMacro:
+  case Mips::BLTUImmMacro:
+  case Mips::BLEUImmMacro:
+  case Mips::BGEUImmMacro:
+  case Mips::BGTUImmMacro:
+  case Mips::BLTLImmMacro:
+  case Mips::BLELImmMacro:
+  case Mips::BGELImmMacro:
+  case Mips::BGTLImmMacro:
+  case Mips::BLTULImmMacro:
+  case Mips::BLEULImmMacro:
+  case Mips::BGEULImmMacro:
+  case Mips::BGTULImmMacro:
     return expandCondBranches(Inst, IDLoc, Instructions);
   case Mips::SDivMacro:
     return expandDiv(Inst, IDLoc, Instructions, false, true);
   case Mips::DSDivMacro:
     return expandDiv(Inst, IDLoc, Instructions, true, true);
   case Mips::UDivMacro:
     return expandDiv(Inst, IDLoc, Instructions, false, false);
   case Mips::DUDivMacro:
MipsAsmParser::expandLoadStoreMultiple(MCInst &Inst, SMLoc IDLoc,
 
   Inst.setOpcode(NewOpcode);
   Instructions.push_back(Inst);
   return false;
 }
 
 bool MipsAsmParser::expandCondBranches(MCInst &Inst, SMLoc IDLoc,
                                        SmallVectorImpl<MCInst> &Instructions) {
+  bool EmittedNoMacroWarning = false;
   unsigned PseudoOpcode = Inst.getOpcode();
   unsigned SrcReg = Inst.getOperand(0).getReg();
-  unsigned TrgReg = Inst.getOperand(1).getReg();
+  const MCOperand &TrgOp = Inst.getOperand(1);
   const MCExpr *OffsetExpr = Inst.getOperand(2).getExpr();
 
   unsigned ZeroSrcOpcode, ZeroTrgOpcode;
   bool ReverseOrderSLT, IsUnsigned, IsLikely, AcceptsEquality;
 
+  unsigned TrgReg;
+  if (TrgOp.isReg())
+    TrgReg = TrgOp.getReg();
+  else if (TrgOp.isImm()) {
+    warnIfNoMacro(IDLoc);
+    EmittedNoMacroWarning = true;
+
+    TrgReg = getATReg(IDLoc);
+    if (!TrgReg)
+      return true;
+
+    switch(PseudoOpcode) {
+    default:
+      llvm_unreachable("unknown opcode for branch pseudo-instruction");
+    case Mips::BLTImmMacro:
+      PseudoOpcode = Mips::BLT;
+      break;
+    case Mips::BLEImmMacro:
+      PseudoOpcode = Mips::BLE;
+      break;
+    case Mips::BGEImmMacro:
+      PseudoOpcode = Mips::BGE;
+      break;
+    case Mips::BGTImmMacro:
+      PseudoOpcode = Mips::BGT;
+      break;
+    case Mips::BLTUImmMacro:
+      PseudoOpcode = Mips::BLTU;
+      break;
+    case Mips::BLEUImmMacro:
+      PseudoOpcode = Mips::BLEU;
+      break;
+    case Mips::BGEUImmMacro:
+      PseudoOpcode = Mips::BGEU;
+      break;
+    case Mips::BGTUImmMacro:
+      PseudoOpcode = Mips::BGTU;
+      break;
+    case Mips::BLTLImmMacro:
+      PseudoOpcode = Mips::BLTL;
+      break;
+    case Mips::BLELImmMacro:
+      PseudoOpcode = Mips::BLEL;
+      break;
+    case Mips::BGELImmMacro:
+      PseudoOpcode = Mips::BGEL;
+      break;
+    case Mips::BGTLImmMacro:
+      PseudoOpcode = Mips::BGTL;
+      break;
+    case Mips::BLTULImmMacro:
+      PseudoOpcode = Mips::BLTUL;
+      break;
+    case Mips::BLEULImmMacro:
+      PseudoOpcode = Mips::BLEUL;
+      break;
+    case Mips::BGEULImmMacro:
+      PseudoOpcode = Mips::BGEUL;
+      break;
+    case Mips::BGTULImmMacro:
+      PseudoOpcode = Mips::BGTUL;
+      break;
+    }
+
+    if (loadImmediate(TrgOp.getImm(), TrgReg, Mips::NoRegister, !isGP64bit(),
+                      false, IDLoc, Instructions))
+      return true;
+  }
+
   switch (PseudoOpcode) {
   case Mips::BLT:
   case Mips::BLTU:
   case Mips::BLTL:
   case Mips::BLTUL:
     AcceptsEquality = false;
     ReverseOrderSLT = false;
     IsUnsigned = ((PseudoOpcode == Mips::BLTU) || (PseudoOpcode == Mips::BLTUL));
bool MipsAsmParser::expandCondBranches(MCInst &Inst, SMLoc IDLoc,
   }
 
   // If neither the SrcReg nor the TrgReg are $0, we need AT to perform the
   // expansions. If it is not available, we return.
   unsigned ATRegNum = getATReg(IDLoc);
   if (!ATRegNum)
     return true;
 
+  if (!EmittedNoMacroWarning)
     warnIfNoMacro(IDLoc);
 
   // SLT fits well with 2 of our 4 pseudo-branches:
   //   BLT, where $rs < $rt, translates into "slt $at, $rs, $rt" and
   //   BGT, where $rs > $rt, translates into "slt $at, $rt, $rs".
   // If the result of the SLT is 1, we branch, and if it's 0, we don't.
   // This is accomplished by using a BNEZ with the result of the SLT.
   //
   // The other 2 pseudo-branches are opposites of the above 2 (BGE with BLT

lib/Target/Mips/MipsInstrInfo.td

 def BLEL : CondBranchPseudo<"blel">, ISA_MIPS2_NOT_32R6_64R6;
 def BGEL : CondBranchPseudo<"bgel">, ISA_MIPS2_NOT_32R6_64R6;
 def BGTL : CondBranchPseudo<"bgtl">, ISA_MIPS2_NOT_32R6_64R6;
 def BLTUL: CondBranchPseudo<"bltul">, ISA_MIPS2_NOT_32R6_64R6;
 def BLEUL: CondBranchPseudo<"bleul">, ISA_MIPS2_NOT_32R6_64R6;
 def BGEUL: CondBranchPseudo<"bgeul">, ISA_MIPS2_NOT_32R6_64R6;
 def BGTUL: CondBranchPseudo<"bgtul">, ISA_MIPS2_NOT_32R6_64R6;
 
+class CondBranchImmPseudo<string instr_asm> :
+  MipsAsmPseudoInst<(outs), (ins GPR32Opnd:$rs, imm64:$imm, brtarget:$offset),
+                    !strconcat(instr_asm, "\t$rs, $imm, $offset")>;
+
+def BLTImmMacro  : CondBranchImmPseudo<"blt">;
+def BLEImmMacro  : CondBranchImmPseudo<"ble">;
+def BGEImmMacro  : CondBranchImmPseudo<"bge">;
+def BGTImmMacro  : CondBranchImmPseudo<"bgt">;
+def BLTUImmMacro : CondBranchImmPseudo<"bltu">;
+def BLEUImmMacro : CondBranchImmPseudo<"bleu">;
+def BGEUImmMacro : CondBranchImmPseudo<"bgeu">;
+def BGTUImmMacro : CondBranchImmPseudo<"bgtu">;
+def BLTLImmMacro : CondBranchImmPseudo<"bltl">, ISA_MIPS2_NOT_32R6_64R6;
+def BLELImmMacro : CondBranchImmPseudo<"blel">, ISA_MIPS2_NOT_32R6_64R6;
+def BGELImmMacro : CondBranchImmPseudo<"bgel">, ISA_MIPS2_NOT_32R6_64R6;
+def BGTLImmMacro : CondBranchImmPseudo<"bgtl">, ISA_MIPS2_NOT_32R6_64R6;
+def BLTULImmMacro : CondBranchImmPseudo<"bltul">, ISA_MIPS2_NOT_32R6_64R6;
+def BLEULImmMacro : CondBranchImmPseudo<"bleul">, ISA_MIPS2_NOT_32R6_64R6;
+def BGEULImmMacro : CondBranchImmPseudo<"bgeul">, ISA_MIPS2_NOT_32R6_64R6;
+def BGTULImmMacro : CondBranchImmPseudo<"bgtul">, ISA_MIPS2_NOT_32R6_64R6;
+
 // FIXME: Predicates are removed because instructions are matched regardless of
 // predicates, because PredicateControl was not in the hierarchy. This was
 // done to emit more precise error message from expansion function.
 // Once the tablegen-erated errors are made better, this needs to be fixed and
 // predicates needs to be restored.
 
 def SDivMacro : MipsAsmPseudoInst<(outs), (ins GPR32Opnd:$rs, GPR32Opnd:$rt),
                                   "div\t$rs, $rt">; //, ISA_MIPS1_NOT_32R6_64R6;

test/MC/Mips/macro-bcc-imm-bad.s

+# RUN: not llvm-mc %s -arch=mips -mcpu=mips32r2 2>&1 | \
+# RUN:     FileCheck %s --check-prefix=ALL
+
+    .text
+    .set noat
+foo:
+    blt $a2, 16, foo # ALL: :[[@LINE]]:5: error: pseudo-instruction requires $at, which is not available
+    .set at
+    .set noreorder
+    .set nomacro
+    blt $a2, 16, foo # ALL: :[[@LINE]]:5: warning: macro instruction expanded into multiple instructions
+                     # ALL-NOT: :[[@LINE-1]]:5: warning: macro instruction expanded into multiple instructions

test/MC/Mips/macro-bcc-imm.s

+# RUN: llvm-mc %s -arch=mips -mcpu=mips32r2 -show-encoding 2>&1 | \
+# RUN:     FileCheck %s --check-prefix=ALL
+
+    .text
+foo:                      # ALL-LABEL: foo:
+    blt $a2, 16, foo      # ALL: addiu $1, $zero, 16
+                          # ALL: slt   $1, $6, $1
+                          # ALL: bnez  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    ble $a2, 16, foo      # ALL: addiu $1, $zero, 16
+                          # ALL: slt   $1, $1, $6
+                          # ALL: beqz  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bge $a2, 32767, foo   # ALL: addiu $1, $zero, 32767
+                          # ALL: slt   $1, $6, $1
+                          # ALL: beqz  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgt $a2, 32768, foo   # ALL: ori   $1, $zero, 32768
+                          # ALL: slt   $1, $1, $6
+                          # ALL: bnez  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bltu $a2, 16, foo     # ALL: addiu $1, $zero, 16
+                          # ALL: sltu  $1, $6, $1
+                          # ALL: bnez  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bleu $a2, 16, foo     # ALL: addiu $1, $zero, 16
+                          # ALL: sltu  $1, $1, $6
+                          # ALL: beqz  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgeu $a2, 32767, foo  # ALL: addiu $1, $zero, 32767
+                          # ALL: sltu  $1, $6, $1
+                          # ALL: beqz  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgtu $a2, 32768, foo  # ALL: ori   $1, $zero, 32768
+                          # ALL: sltu  $1, $1, $6
+                          # ALL: bnez  $1, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bltl $a2, 16, foo     # ALL: addiu $1, $zero, 16
+                          # ALL: slt   $1, $6, $1
+                          # ALL: bnel  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    blel $a2, 16, foo     # ALL: addiu $1, $zero, 16
+                          # ALL: slt   $1, $1, $6
+                          # ALL: beql  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgel $a2, 32767, foo  # ALL: addiu $1, $zero, 32767
+                          # ALL: slt   $1, $6, $1
+                          # ALL: beql  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgtl $a2, 32768, foo  # ALL: ori   $1, $zero, 32768
+                          # ALL: slt   $1, $1, $6
+                          # ALL: bnel  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bltul $a2, 16, foo    # ALL: addiu $1, $zero, 16
+                          # ALL: sltu  $1, $6, $1
+                          # ALL: bnel  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bleul $a2, 16, foo    # ALL: addiu $1, $zero, 16
+                          # ALL: sltu  $1, $1, $6
+                          # ALL: beql  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgeul $a2, 32767, foo # ALL: addiu $1, $zero, 32767
+                          # ALL: sltu  $1, $6, $1
+                          # ALL: beql  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16
+    bgtul $a2, 65536, foo # ALL: lui   $1, 1
+                          # ALL: sltu  $1, $1, $6
+                          # ALL: bnel  $1, $zero, foo
+                          # ALL: # fixup A - offset: 0, value: foo-4, kind: fixup_Mips_PC16