[LoongArch] Ensure pcaddu18i and jirl adjacency in tail calls for correct relocation

llvm/lib/Target/LoongArch/LoongArchExpandPseudoInsts.cpp

@@ -165,11 +165,9 @@ bool LoongArchPreRAExpandPseudo::expandMI(
   case LoongArch::PseudoLA_TLS_DESC_LARGE:
     return expandLoadAddressTLSDesc(MBB, MBBI, NextMBBI, /*Large=*/true);
   case LoongArch::PseudoCALL:
-  case LoongArch::PseudoCALL_MEDIUM:
   case LoongArch::PseudoCALL_LARGE:
     return expandFunctionCALL(MBB, MBBI, NextMBBI, /*IsTailCall=*/false);
   case LoongArch::PseudoTAIL:
-  case LoongArch::PseudoTAIL_MEDIUM:
   case LoongArch::PseudoTAIL_LARGE:
     return expandFunctionCALL(MBB, MBBI, NextMBBI, /*IsTailCall=*/true);
   case LoongArch::PseudoBRIND:
@@ -545,7 +543,7 @@ bool LoongArchPreRAExpandPseudo::expandFunctionCALL(
 
   switch (MF->getTarget().getCodeModel()) {
   default:
-    report_fatal_error("Unsupported code model");
+    report_fatal_error("Unexpected code model");
     break;
   case CodeModel::Small: {
     // CALL:
@@ -556,31 +554,6 @@ bool LoongArchPreRAExpandPseudo::expandFunctionCALL(
     CALL = BuildMI(MBB, MBBI, DL, TII->get(Opcode)).add(Func);
     break;
   }
-  case CodeModel::Medium: {
-    // CALL:
-    // pcaddu18i $ra, %call36(func)
-    // jirl      $ra, $ra, 0
-    // TAIL:
-    // pcaddu18i $scratch, %call36(func)
-    // jirl      $r0, $scratch, 0
-    Opcode =
-        IsTailCall ? LoongArch::PseudoJIRL_TAIL : LoongArch::PseudoJIRL_CALL;
-    Register ScratchReg =
-        IsTailCall
-            ? MF->getRegInfo().createVirtualRegister(&LoongArch::GPRRegClass)
-            : LoongArch::R1;
-    MachineInstrBuilder MIB =
-        BuildMI(MBB, MBBI, DL, TII->get(LoongArch::PCADDU18I), ScratchReg);
-
-    CALL =
-        BuildMI(MBB, MBBI, DL, TII->get(Opcode)).addReg(ScratchReg).addImm(0);
-
-    if (Func.isSymbol())
-      MIB.addExternalSymbol(Func.getSymbolName(), LoongArchII::MO_CALL36);
-    else
-      MIB.addDisp(Func, 0, LoongArchII::MO_CALL36);
-    break;
-  }
   case CodeModel::Large: {
     // Emit the 5-insn large address load sequence, either directly or
     // indirectly in case of going through the GOT, then JIRL_TAIL or
@@ -671,6 +644,10 @@ class LoongArchExpandPseudo : public MachineFunctionPass {
                 MachineBasicBlock::iterator &NextMBBI);
   bool expandCopyCFR(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
                      MachineBasicBlock::iterator &NextMBBI);
+  bool expandFunctionCALL(MachineBasicBlock &MBB,
+                          MachineBasicBlock::iterator MBBI,
+                          MachineBasicBlock::iterator &NextMBBI,
+                          bool IsTailCall);
 };
 
 char LoongArchExpandPseudo::ID = 0;
@@ -705,6 +682,10 @@ bool LoongArchExpandPseudo::expandMI(MachineBasicBlock &MBB,
   switch (MBBI->getOpcode()) {
   case LoongArch::PseudoCopyCFR:
     return expandCopyCFR(MBB, MBBI, NextMBBI);
+  case LoongArch::PseudoCALL_MEDIUM:
+    return expandFunctionCALL(MBB, MBBI, NextMBBI, /*IsTailCall=*/false);
+  case LoongArch::PseudoTAIL_MEDIUM:
+    return expandFunctionCALL(MBB, MBBI, NextMBBI, /*IsTailCall=*/true);
   }
 
   return false;
@@ -763,6 +744,54 @@ bool LoongArchExpandPseudo::expandCopyCFR(
   return true;
 }
 
+bool LoongArchExpandPseudo::expandFunctionCALL(
+    MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
+    MachineBasicBlock::iterator &NextMBBI, bool IsTailCall) {
+  MachineFunction *MF = MBB.getParent();
+  MachineInstr &MI = *MBBI;
+  DebugLoc DL = MI.getDebugLoc();
+  const MachineOperand &Func = MI.getOperand(0);
+  MachineInstrBuilder CALL;
+  unsigned Opcode;
+
+  switch (MF->getTarget().getCodeModel()) {
+  default:
+    report_fatal_error("Unexpected code model");
+    break;
+  case CodeModel::Medium: {
+    // CALL:
+    // pcaddu18i $ra, %call36(func)
+    // jirl      $ra, $ra, 0
+    // TAIL:
+    // pcaddu18i $t8, %call36(func)
+    // jirl      $r0, $t8, 0
+    Opcode =
+        IsTailCall ? LoongArch::PseudoJIRL_TAIL : LoongArch::PseudoJIRL_CALL;
+    Register ScratchReg = IsTailCall ? LoongArch::R20 : LoongArch::R1;
+    MachineInstrBuilder MIB =
+        BuildMI(MBB, MBBI, DL, TII->get(LoongArch::PCADDU18I), ScratchReg);
+
+    CALL =
+        BuildMI(MBB, MBBI, DL, TII->get(Opcode)).addReg(ScratchReg).addImm(0);
+
+    if (Func.isSymbol())
+      MIB.addExternalSymbol(Func.getSymbolName(), LoongArchII::MO_CALL36);
+    else
+      MIB.addDisp(Func, 0, LoongArchII::MO_CALL36);
+    break;
+  }
+  }
+
+  // Transfer implicit operands.
+  CALL.copyImplicitOps(MI);
+
+  // Transfer MI flags.
+  CALL.setMIFlags(MI.getFlags());
+
+  MI.eraseFromParent();
+  return true;
+}
+
 } // end namespace
 
 INITIALIZE_PASS(LoongArchPreRAExpandPseudo, "loongarch-prera-expand-pseudo",

llvm/lib/Target/LoongArch/LoongArchInstrInfo.cpp

@@ -391,9 +391,6 @@ bool LoongArchInstrInfo::isSchedulingBoundary(const MachineInstr &MI,
   //
   // The following instruction patterns are prohibited from being reordered:
   //
-  // * pcaddu18 $ra, %call36(s)
-  //   jirl     $ra, $ra, 0
-  //
   // * pcalau12i $a0, %pc_hi20(s)
   //   addi.d $a1, $zero, %pc_lo12(s)
   //   lu32i.d $a1, %pc64_lo20(s)
@@ -413,10 +410,6 @@ bool LoongArchInstrInfo::isSchedulingBoundary(const MachineInstr &MI,
   // boundaries, and the instructions between them are guaranteed to be
   // ordered according to data dependencies.
   switch (MI.getOpcode()) {
-  case LoongArch::PCADDU18I:
-    if (MI.getOperand(1).getTargetFlags() == LoongArchII::MO_CALL36)
-      return true;
-    break;
   case LoongArch::PCALAU12I: {
     auto AddI = std::next(MII);
     if (AddI == MIE || AddI->getOpcode() != LoongArch::ADDI_D)

llvm/lib/Target/LoongArch/LoongArchInstrInfo.td

@@ -1484,7 +1484,7 @@ def : Pat<(loongarch_call tglobaladdr:$func), (PseudoCALL tglobaladdr:$func)>;
 def : Pat<(loongarch_call texternalsym:$func), (PseudoCALL texternalsym:$func)>;
 
 // Function call with 'Medium' code model.
-let isCall = 1, Defs = [R1] in
+let isCall = 1, Defs = [R1, R20], Size = 8 in
 def PseudoCALL_MEDIUM : Pseudo<(outs), (ins bare_symbol:$func)>;
 
 let Predicates = [IsLA64] in {
@@ -1533,7 +1533,8 @@ def : Pat<(loongarch_tail (iPTR texternalsym:$dst)),
           (PseudoTAIL texternalsym:$dst)>;
 
 // Tail call with 'Medium' code model.
-let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1, Uses = [R3] in
+let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1,
+    Uses = [R3], Defs = [R20], Size = 8 in
 def PseudoTAIL_MEDIUM : Pseudo<(outs), (ins bare_symbol:$dst)>;
 
 let Predicates = [IsLA64] in {

llvm/test/CodeGen/LoongArch/code-models.ll

@@ -105,8 +105,8 @@ define i32 @caller_tail(i32 %i) nounwind {
 ;
 ; MEDIUM-LABEL: caller_tail:
 ; MEDIUM:       # %bb.0: # %entry
-; MEDIUM-NEXT:    pcaddu18i $a1, %call36(callee_tail)
-; MEDIUM-NEXT:    jr $a1
+; MEDIUM-NEXT:    pcaddu18i $t8, %call36(callee_tail)
+; MEDIUM-NEXT:    jr $t8
 ;
 ; LARGE-LABEL: caller_tail:
 ; LARGE:       # %bb.0: # %entry

llvm/test/CodeGen/LoongArch/expand-adjacency.ll

@@ -27,11 +27,8 @@ declare i32 @callee_tail(i32 %i)
 
 define i32 @caller_call_tail(i32 %i) nounwind {
 ; MEDIUM-LABEL: caller_call_tail:
-; MEDIUM:         pcaddu18i $a1, %call36(callee_tail)
-; MEDIUM-NEXT:    ld.d {{.*}}
-; MEDIUM-NEXT:    ld.d {{.*}}
-; MEDIUM-NEXT:    addi.d {{.*}}
-; MEDIUM-NEXT:    jr $a1
+; MEDIUM:         pcaddu18i $t8, %call36(callee_tail)
+; MEDIUM-NEXT:    jr $t8
 ;
 ; LARGE-LABEL: caller_call_tail:
 ; LARGE:         pcalau12i [[REG1:\$[a-z0-9]+]], %got_pc_hi20(callee_tail)