[mips][mips64r6] b(ge|lt)zal are not available on MIPS32r6/MIPS64r6 and bal is a normal instruction

Summary:
b(ge|lt)zal have been removed in MIPS32r6/MIPS64r6. However, bal (an alias
for 'bgezal $zero, $offset') still remains with the same encoding it had
prior to MIPS32r6/MIPS64r6.

Updated the MipsNaCLELFStreamer, and MipsLongBranch to correctly handle the
MIPS32r6/MIPS64r6 BAL instruction in addition to the existing BAL_BR pseudo.

No changes were required to the CodeGen test that looks for BAL
(test/CodeGen/Mips/longbranch.ll) since the new instruction has the same
syntax.

Depends on D4113

Reviewers: jkolek, zoran.jovanovic, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D4114

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210898 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 45 insertions, 13 deletions

diff --git a/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp b/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp
index 9a7fc85e91..2dc3b7bf81 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp
@@ -64,6 +64,7 @@ private:
       return false;
 
     case Mips::JAL:
+    case Mips::BAL:
     case Mips::BAL_BR:
     case Mips::BLTZAL:
     case Mips::BGEZAL:
diff --git a/lib/Target/Mips/Mips32r6InstrFormats.td b/lib/Target/Mips/Mips32r6InstrFormats.td
index 81c569b64e..5c579633b1 100644
--- a/lib/Target/Mips/Mips32r6InstrFormats.td
+++ b/lib/Target/Mips/Mips32r6InstrFormats.td
@@ -64,6 +64,7 @@ def OPCODE5_BC1EQZ : OPCODE5<0b01001>;
 def OPCODE5_BC1NEZ : OPCODE5<0b01101>;
 def OPCODE5_BC2EQZ : OPCODE5<0b01001>;
 def OPCODE5_BC2NEZ : OPCODE5<0b01101>;
+def OPCODE5_BGEZAL : OPCODE5<0b10001>;
 
 class OPCODE6<bits<6> Val> {
   bits<6> Value = Val;
@@ -145,6 +146,17 @@ class DAUI_FM : AUI_FM {
   let Inst{31-26} = OPGROUP_DAUI.Value;
 }
 
+class BAL_FM : MipsR6Inst {
+  bits<16> offset;
+
+  bits<32> Inst;
+
+  let Inst{31-26} = OPGROUP_REGIMM.Value;
+  let Inst{25-21} = 0b00000;
+  let Inst{20-16} = OPCODE5_BGEZAL.Value;
+  let Inst{15-0} = offset;
+}
+
 class COP1_2R_FM<bits<6> funct, FIELD_FMT Format> : MipsR6Inst {
   bits<5> fs;
   bits<5> fd;
diff --git a/lib/Target/Mips/Mips32r6InstrInfo.td b/lib/Target/Mips/Mips32r6InstrInfo.td
index ea164208be..2ed580e67a 100644
--- a/lib/Target/Mips/Mips32r6InstrInfo.td
+++ b/lib/Target/Mips/Mips32r6InstrInfo.td
@@ -26,8 +26,6 @@ include "Mips32r6InstrFormats.td"
 // Reencoded: sdc2
 // Reencoded: swc2
 // Removed: bc1any2, bc1any4
-// Removed: bgezal
-// Removed: bltzal
 // Rencoded: [ls][wd]c2
 
 def brtarget21 : Operand<OtherVT> {
@@ -66,6 +64,7 @@ class ALUIPC_ENC : PCREL16_FM<OPCODE5_ALUIPC>;
 class AUI_ENC    : AUI_FM;
 class AUIPC_ENC  : PCREL16_FM<OPCODE5_AUIPC>;
 
+class BAL_ENC   : BAL_FM;
 class BALC_ENC  : BRANCH_OFF26_FM<0b111010>;
 class BC_ENC    : BRANCH_OFF26_FM<0b110010>;
 class BEQC_ENC  : CMP_BRANCH_2R_OFF16_FM<OPGROUP_ADDI>,
@@ -309,6 +308,12 @@ class CMP_CBR_RT_Z_DESC_BASE<string instr_asm, DAGOperand opnd,
   list<Register> Defs = [AT];
 }
 
+class BAL_DESC : BC_DESC_BASE<"bal", brtarget> {
+  bit isCall = 1;
+  bit hasDelaySlot = 1;
+  list<Register> Defs = [RA];
+}
+
 class BALC_DESC : BC_DESC_BASE<"balc", brtarget26> {
   bit isCall = 1;
   list<Register> Defs = [RA];
@@ -535,6 +540,7 @@ def ALIGN : ALIGN_ENC, ALIGN_DESC, ISA_MIPS32R6;
 def ALUIPC : ALUIPC_ENC, ALUIPC_DESC, ISA_MIPS32R6;
 def AUI : AUI_ENC, AUI_DESC, ISA_MIPS32R6;
 def AUIPC : AUIPC_ENC, AUIPC_DESC, ISA_MIPS32R6;
+def BAL : BAL_ENC, BAL_DESC, ISA_MIPS32R6;
 def BALC : BALC_ENC, BALC_DESC, ISA_MIPS32R6;
 def BC1EQZ : BC1EQZ_ENC, BC1EQZ_DESC, ISA_MIPS32R6;
 def BC1NEZ : BC1NEZ_ENC, BC1NEZ_DESC, ISA_MIPS32R6;
diff --git a/lib/Target/Mips/MipsInstrInfo.td b/lib/Target/Mips/MipsInstrInfo.td
index a258af68d4..07b9fbc3c8 100644
--- a/lib/Target/Mips/MipsInstrInfo.td
+++ b/lib/Target/Mips/MipsInstrInfo.td
@@ -1188,8 +1188,10 @@ let AdditionalPredicates = [NotInMicroMips] in {
 
 // FIXME: JALX really requires either MIPS16 or microMIPS in addition to MIPS32.
 def JALX  : JumpLink<"jalx", calltarget>, FJ<0x1D>, ISA_MIPS32_NOT_32R6_64R6;
-def BGEZAL : MMRel, BGEZAL_FT<"bgezal", brtarget, GPR32Opnd>, BGEZAL_FM<0x11>;
-def BLTZAL : MMRel, BGEZAL_FT<"bltzal", brtarget, GPR32Opnd>, BGEZAL_FM<0x10>;
+def BGEZAL : MMRel, BGEZAL_FT<"bgezal", brtarget, GPR32Opnd>, BGEZAL_FM<0x11>,
+             ISA_MIPS1_NOT_32R6_64R6;
+def BLTZAL : MMRel, BGEZAL_FT<"bltzal", brtarget, GPR32Opnd>, BGEZAL_FM<0x10>,
+             ISA_MIPS1_NOT_32R6_64R6;
 def BAL_BR : BAL_BR_Pseudo<BGEZAL>;
 def TAILCALL : TailCall<J>;
 def TAILCALL_R : TailCallReg<GPR32Opnd, JR>;
@@ -1366,7 +1368,8 @@ def : MipsInstAlias<"move $dst, $src",
       GPR_32 {
   let AdditionalPredicates = [NotInMicroMips];
 }
-def : MipsInstAlias<"bal $offset", (BGEZAL ZERO, brtarget:$offset), 0>;
+def : MipsInstAlias<"bal $offset", (BGEZAL ZERO, brtarget:$offset), 0>,
+      ISA_MIPS1_NOT_32R6_64R6;
 def : MipsInstAlias<"addu $rs, $rt, $imm",
                     (ADDiu GPR32Opnd:$rs, GPR32Opnd:$rt, simm16:$imm), 0>;
 def : MipsInstAlias<"add $rs, $rt, $imm",
diff --git a/lib/Target/Mips/MipsLongBranch.cpp b/lib/Target/Mips/MipsLongBranch.cpp
index e72db15c98..c6838a37be 100644
--- a/lib/Target/Mips/MipsLongBranch.cpp
+++ b/lib/Target/Mips/MipsLongBranch.cpp
@@ -266,6 +266,13 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) {
     LongBrMBB->addSuccessor(BalTgtMBB);
     BalTgtMBB->addSuccessor(TgtMBB);
 
+    // We must select between the MIPS32r6/MIPS64r6 BAL (which is a normal
+    // instruction) and the pre-MIPS32r6/MIPS64r6 definition (which is an
+    // pseudo-instruction wrapping BGEZAL).
+
+    const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>();
+    unsigned BalOp = Subtarget.hasMips32r6() ? Mips::BAL : Mips::BAL_BR;
+
     if (ABI != MipsSubtarget::N64) {
       // $longbr:
       //  addiu $sp, $sp, -8
@@ -307,9 +314,11 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) {
       BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::LONG_BRANCH_LUi), Mips::AT)
         .addMBB(TgtMBB).addMBB(BalTgtMBB);
       MIBundleBuilder(*LongBrMBB, Pos)
-        .append(BuildMI(*MF, DL, TII->get(Mips::BAL_BR)).addMBB(BalTgtMBB))
-        .append(BuildMI(*MF, DL, TII->get(Mips::LONG_BRANCH_ADDiu), Mips::AT)
-                  .addReg(Mips::AT).addMBB(TgtMBB).addMBB(BalTgtMBB));
+          .append(BuildMI(*MF, DL, TII->get(BalOp)).addMBB(BalTgtMBB))
+          .append(BuildMI(*MF, DL, TII->get(Mips::LONG_BRANCH_ADDiu), Mips::AT)
+                      .addReg(Mips::AT)
+                      .addMBB(TgtMBB)
+                      .addMBB(BalTgtMBB));
 
       Pos = BalTgtMBB->begin();
 
@@ -379,11 +388,12 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) {
         .addReg(Mips::AT_64).addImm(16);
 
       MIBundleBuilder(*LongBrMBB, Pos)
-        .append(BuildMI(*MF, DL, TII->get(Mips::BAL_BR)).addMBB(BalTgtMBB))
-        .append(BuildMI(*MF, DL, TII->get(Mips::LONG_BRANCH_DADDiu),
-                        Mips::AT_64).addReg(Mips::AT_64)
-                                    .addMBB(TgtMBB, MipsII::MO_ABS_LO)
-                                    .addMBB(BalTgtMBB));
+          .append(BuildMI(*MF, DL, TII->get(BalOp)).addMBB(BalTgtMBB))
+          .append(
+              BuildMI(*MF, DL, TII->get(Mips::LONG_BRANCH_DADDiu), Mips::AT_64)
+                  .addReg(Mips::AT_64)
+                  .addMBB(TgtMBB, MipsII::MO_ABS_LO)
+                  .addMBB(BalTgtMBB));
 
       Pos = BalTgtMBB->begin();