[globalisel][tablegen] Simplify named operand/operator lookups and fix a wrong-code bug this revealed.

[dsanders]

Summary

Operand variable lookups are now performed by the RuleMatcher rather than
searching the whole matcher hierarchy for a match. This revealed a wrong-code
bug that currently affects ARM and X86 where patterns that use a variable more
than once in the match pattern will be imported but won't check that the
operands are identical. This can cause the tablegen-erated matcher to
accept matches that should be rejected.

Depends on D36569

[dsanders]

Rebase

[dsanders]

Rebase and ping

[qcolombet]

Looks mostly good.
Couple of comments below.

include/llvm/CodeGen/GlobalISel/InstructionSelector.h

158 ↗

(On Diff #118446)

Food for thought: I wonder if we should use a different name like CheckIsSame, because when I see tie, it makes me think of the tie operand in the MCDesc and that's not what this is.
I believe I won't be the only one confused by this at first :).

test/CodeGen/X86/GlobalISel/select-blsr.mir

15 ↗

(On Diff #118446)

Could you add a comment explaining what this test is checking, beyond blsr selection?
In particular, I would have expected something about the fact that the operands of the both G_ADD and G_AND should be the same.

Could you also add a negative test case?
In particular, one that would have match with the bug but does now. I expect you could just change the parameters of one of G_ADD or G_ADD.

utils/TableGen/GlobalISelEmitter.cpp

2091 ↗

(On Diff #118446)

This is an optimization, not a correctness problem, right?

2092 ↗

(On Diff #118446)

Could we have this check pushed into ::addPredicate?
That way we wouldn't have to spread it all around.

[dsanders]

include/llvm/CodeGen/GlobalISel/InstructionSelector.h

158 ↗

(On Diff #118446)

I see your point, I'll rename it. The reason I went with Tie was that the use of the opcode is triggered by using the same name multiple times like the MC layer.

test/CodeGen/X86/GlobalISel/select-blsr.mir

15 ↗

(On Diff #118446)

Ok

utils/TableGen/GlobalISelEmitter.cpp

2091 ↗

(On Diff #118446)

That's right. It's not wrong to check the original predicate again, it just saves on work.

2092 ↗

(On Diff #118446)

I think so, I'll give it a go

[dsanders]

Fix nits aside from the addPredicate change.

[dsanders]

include/llvm/CodeGen/GlobalISel/InstructionSelector.h

158 ↗

(On Diff #118446)

I also renamed related functions like isTied().

utils/TableGen/GlobalISelEmitter.cpp

2092 ↗

(On Diff #118446)

I managed to make this work. addPredicate() now returns an optional and for the OperandMatcher will avoid adding more predicates when isSameAsAnotherOperand() is true.

The importer will now give up on a rule if isSameAsAnotherOperand() is true and it's asked to create a sub-instruction matcher. As far as I know, this situation never occurred but if it did it wouldn't have checked they were the same operand and would therefore have matched cases it shouldn't. It's technically possible to import this case but I don't think we should. It would occur for something like (add $src1:(sub $a, $b), $src1:(sub $a, $b)) but this only works if both $src1 sub-patterns are identical. If they differ, then matching is impossible and we ought to warn about that. However, rather than verify that the sub-patterns are identical, I think it makes more sense to encourage writing it as (add ($src1:(sub $a, $b), $src1). Without the redundancy, impossible rules can't occur.

llvm/trunk/include/llvm/CodeGen/GlobalISel/InstructionSelector.h

enum {
   /// - OpIdx - Operand index
   GIM_CheckIsMBB,
 
   /// Check if the specified operand is safe to fold into the current
   /// instruction.
   /// - InsnID - Instruction ID
   GIM_CheckIsSafeToFold,
 
+  /// Check the specified operands are identical.
+  /// - InsnID - Instruction ID
+  /// - OpIdx - Operand index
+  /// - OtherInsnID - Other instruction ID
+  /// - OtherOpIdx - Other operand index
+  GIM_CheckIsSameOperand,
+
   /// Fail the current try-block, or completely fail to match if there is no
   /// current try-block.
   GIM_Reject,
 
   //=== Renderers ===
 
   /// Mutate an instruction
   /// - NewInsnID - Instruction ID to define

llvm/trunk/include/llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h

case GIM_CheckIsSafeToFold: {
                    << "])\n");
       assert(State.MIs[InsnID] != nullptr && "Used insn before defined");
       if (!isObviouslySafeToFold(*State.MIs[InsnID])) {
         if (handleReject() == RejectAndGiveUp)
           return false;
       }
       break;
     }
-
+    case GIM_CheckIsSameOperand: {
+      int64_t InsnID = MatchTable[CurrentIdx++];
+      int64_t OpIdx = MatchTable[CurrentIdx++];
+      int64_t OtherInsnID = MatchTable[CurrentIdx++];
+      int64_t OtherOpIdx = MatchTable[CurrentIdx++];
+      DEBUG(dbgs() << CurrentIdx << ": GIM_CheckIsSameOperand(MIs[" << InsnID
+                   << "][" << OpIdx << "], MIs[" << OtherInsnID << "]["
+                   << OtherOpIdx << "])\n");
+      assert(State.MIs[InsnID] != nullptr && "Used insn before defined");
+      assert(State.MIs[OtherInsnID] != nullptr && "Used insn before defined");
+      State.MIs[InsnID]->getOperand(OpIdx).dump();
+      State.MIs[OtherInsnID]->getOperand(OtherOpIdx).dump();
+      if (!State.MIs[InsnID]->getOperand(OpIdx).isIdenticalTo(
+              State.MIs[OtherInsnID]->getOperand(OtherInsnID))) {
+        if (handleReject() == RejectAndGiveUp)
+          return false;
+      }
+      break;
+    }
     case GIM_Reject:
       DEBUG(dbgs() << CurrentIdx << ": GIM_Reject");
       if (handleReject() == RejectAndGiveUp)
         return false;
       break;
 
     case GIR_MutateOpcode: {
       int64_t OldInsnID = MatchTable[CurrentIdx++];

llvm/trunk/test/CodeGen/X86/GlobalISel/select-blsr.mir

+# RUN: llc -mtriple=x86_64-linux-gnu -mattr=+bmi -global-isel -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s
+#
+# Test that rules where multiple operands must be the same operand successfully
+# match. Also test that the rules do not match when they're not the same
+# operand.
+
+---
+name:            test_blsr32rr
+# CHECK-LABEL: name:  test_blsr32rr
+alignment:       4
+legalized:       true
+regBankSelected: true
+# CHECK:       registers:
+# CHECK-NEXT:     - { id: 0, class: gr32, preferred-register: '' }
+# CHECK-NEXT:     - { id: 1, class: gpr, preferred-register: '' }
+# CHECK-NEXT:     - { id: 2, class: gpr, preferred-register: '' }
+# CHECK-NEXT:     - { id: 3, class: gr32, preferred-register: '' }
+registers:
+  - { id: 0, class: gpr }
+  - { id: 1, class: gpr }
+  - { id: 2, class: gpr }
+  - { id: 3, class: gpr }
+# G_ADD and G_AND both use %0 so we should match this.
+# CHECK: %3 = BLSR32rr %0
+body:             |
+  bb.1:
+    liveins: %edi
+
+    %0(s32) = COPY %edi
+    %1(s32) = G_CONSTANT i32 -1
+    %2(s32) = G_ADD %0, %1
+    %3(s32) = G_AND %2, %0
+    %edi = COPY %3
+
+...
+---
+name:            test_blsr32rr_nomatch
+# CHECK-LABEL: name:  test_blsr32rr_nomatch
+alignment:       4
+legalized:       true
+regBankSelected: true
+registers:
+  - { id: 0, class: gpr }
+  - { id: 1, class: gpr }
+  - { id: 2, class: gpr }
+  - { id: 3, class: gpr }
+# G_ADD and G_AND use different operands so we shouldn't match this.
+# CHECK-NOT: BLSR32rr
+body:             |
+  bb.1:
+    liveins: %edi
+
+    %0(s32) = COPY %edi
+    %1(s32) = G_CONSTANT i32 -1
+    %2(s32) = G_ADD %1, %1
+    %3(s32) = G_AND %2, %0
+    %edi = COPY %3
+...

llvm/trunk/test/TableGen/GlobalISelEmitter.td

 // CHECK-NEXT:    GIR_MutateOpcode, /*InsnID*/0, /*RecycleInsnID*/0, /*Opcode*/MyTarget::ADD,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
 // CHECK-NEXT:  // Label 2: @[[LABEL]]
 
 def ADD : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2),
             [(set GPR32:$dst, (add GPR32:$src1, GPR32:$src2))]>;
 
-//===- Test a simple pattern with ValueType operands. ----------------------===//
+//===- Test a pattern with a tied operand in the matcher ------------------===//
 
 // CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 3*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_ADD,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
+// CHECK-NEXT:    // MIs[0] src{{$}}
+// CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
+// CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
+// CHECK-NEXT:    // MIs[0] src{{$}}
+// CHECK-NEXT:    GIM_CheckIsSameOperand, /*MI*/0, /*OpIdx*/2, /*OtherMI*/0, /*OtherOpIdx*/1,
+// CHECK-NEXT:    // (add:{ *:[i32] } GPR32:{ *:[i32] }:$src, GPR32:{ *:[i32] }:$src) => (DOUBLE:{ *:[i32] } GPR32:{ *:[i32] }:$src)
+// CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::DOUBLE,
+// CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
+// CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src
+// CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
+// CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
+// CHECK-NEXT:    GIR_Done,
+// CHECK-NEXT:  // Label 3: @[[LABEL]]
+
+def DOUBLE : I<(outs GPR32:$dst), (ins GPR32:$src), [(set GPR32:$dst, (add GPR32:$src, GPR32:$src))]>;
+
+//===- Test a simple pattern with ValueType operands. ----------------------===//
+
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 4*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
+// CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_ADD,
+// CHECK-NEXT:    // MIs[0] dst
+// CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
+// CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    // MIs[0] src2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    // (add:{ *:[i32] } i32:{ *:[i32] }:$src1, i32:{ *:[i32] }:$src2) => (ADD:{ *:[i32] } i32:{ *:[i32] }:$src1, i32:{ *:[i32] }:$src2)
 // CHECK-NEXT:    GIR_MutateOpcode, /*InsnID*/0, /*RecycleInsnID*/0, /*Opcode*/MyTarget::ADD,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 3: @[[LABEL]]
+// CHECK-NEXT:  // Label 4: @[[LABEL]]
 
 def : Pat<(add i32:$src1, i32:$src2),
           (ADD i32:$src1, i32:$src2)>;
 
 //===- Test a simple pattern with an intrinsic. ---------------------------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 4*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 5*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_INTRINSIC,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 1
 // CHECK-NEXT:    GIM_CheckIntrinsicID, /*MI*/0, /*Op*/1, Intrinsic::mytarget_nop,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/2, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // (intrinsic_wo_chain:{ *:[i32] } [[ID:[0-9]+]]:{ *:[iPTR] }, GPR32:{ *:[i32] }:$src1) => (MOV:{ *:[i32] } GPR32:{ *:[i32] }:$src1)
 
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOV,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/2, // src1
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 4: @[[LABEL]]
+// CHECK-NEXT:  // Label 5: @[[LABEL]]
 
 def MOV : I<(outs GPR32:$dst), (ins GPR32:$src1),
             [(set GPR32:$dst, (int_mytarget_nop GPR32:$src1))]>;
 
 //===- Test a nested instruction match. -----------------------------------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 5*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 6*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckFeatures, GIFBS_HasA,
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_RecordInsn, /*DefineMI*/1, /*MI*/0, /*OpIdx*/1, // MIs[1]
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/1, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_MUL,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,

 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MULADD,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/2, // src3
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 5: @[[LABEL]]
+// CHECK-NEXT:  // Label 6: @[[LABEL]]
 
 // We also get a second rule by commutativity.
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 6*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 7*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckFeatures, GIFBS_HasA,
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_RecordInsn, /*DefineMI*/1, /*MI*/0, /*OpIdx*/2,
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/1, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_MUL,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,

 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MULADD,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src3
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 6: @[[LABEL]]
+// CHECK-NEXT:  // Label 7: @[[LABEL]]
 
 def MULADD : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2, GPR32:$src3),
                [(set GPR32:$dst,
                      (mul (add GPR32:$src1, GPR32:$src2), GPR32:$src3))]>,
              Requires<[HasA]>;
 
 //===- Test another simple pattern with regclass operands. ----------------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 7*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 8*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckFeatures, GIFBS_HasA_HasB_HasC,
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_MUL,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/2, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // (mul:{ *:[i32] } GPR32:{ *:[i32] }:$src1, GPR32:{ *:[i32] }:$src2) => (MUL:{ *:[i32] } GPR32:{ *:[i32] }:$src2, GPR32:{ *:[i32] }:$src1)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MUL,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 7: @[[LABEL]]
+// CHECK-NEXT:  // Label 8: @[[LABEL]]
 
 def MUL : I<(outs GPR32:$dst), (ins GPR32:$src2, GPR32:$src1),
              [(set GPR32:$dst, (mul GPR32:$src1, GPR32:$src2))]>,
           Requires<[HasA, HasB, HasC]>;
 
 //===- Test a more complex multi-instruction match. -----------------------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 8*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 9*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckFeatures, GIFBS_HasA,
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_RecordInsn, /*DefineMI*/1, /*MI*/0, /*OpIdx*/1, // MIs[1]
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/1, /*Expected*/3,
 // CHECK-NEXT:    GIM_RecordInsn, /*DefineMI*/2, /*MI*/0, /*OpIdx*/2, // MIs[2]
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/2, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_SUB,
 // CHECK-NEXT:    // MIs[0] dst

 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/2, /*OpIdx*/1, // src3
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/2, /*OpIdx*/2, // src4
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 8: @[[LABEL]]
+// CHECK-NEXT:  // Label 9: @[[LABEL]]
 
 def INSNBOB : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2, GPR32:$src3, GPR32:$src4),
                  [(set GPR32:$dst,
                       (sub (sub GPR32:$src1, GPR32:$src2), (sub GPR32:$src3, GPR32:$src4)))]>,
                Requires<[HasA]>;
 
 //===- Test a pattern with ComplexPattern operands. -----------------------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 9*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 10*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_SUB,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckComplexPattern, /*MI*/0, /*Op*/2, /*Renderer*/0, GICP_gi_complex,
 // CHECK-NEXT:    // (sub:{ *:[i32] } GPR32:{ *:[i32] }:$src1, complex:{ *:[i32] }:$src2) => (INSN1:{ *:[i32] } GPR32:{ *:[i32] }:$src1, complex:{ *:[i32] }:$src2)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::INSN1,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_ComplexRenderer, /*InsnID*/0, /*RendererID*/0,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 9: @[[LABEL]]
+// CHECK-NEXT:  // Label 10: @[[LABEL]]
 
 def INSN1 : I<(outs GPR32:$dst), (ins GPR32:$src1, complex:$src2), []>;
 def : Pat<(sub GPR32:$src1, complex:$src2), (INSN1 GPR32:$src1, complex:$src2)>;
 
 //===- Test a simple pattern with a default operand. ----------------------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 10*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 11*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_XOR,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckConstantInt, /*MI*/0, /*Op*/2, -2
 // CHECK-NEXT:    // (xor:{ *:[i32] } GPR32:{ *:[i32] }:$src1, -2:{ *:[i32] }) => (XORI:{ *:[i32] } GPR32:{ *:[i32] }:$src1)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::XORI,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddImm, /*InsnID*/0, /*Imm*/-1,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 10: @[[LABEL]]
+// CHECK-NEXT:  // Label 11: @[[LABEL]]
 
 // The -2 is just to distinguish it from the 'not' case below.
 def XORI : I<(outs GPR32:$dst), (ins m1:$src2, GPR32:$src1),
              [(set GPR32:$dst, (xor GPR32:$src1, -2))]>;
 
 //===- Test a simple pattern with a default register operand. -------------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 11*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 12*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_XOR,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckConstantInt, /*MI*/0, /*Op*/2, -3
 // CHECK-NEXT:    // (xor:{ *:[i32] } GPR32:{ *:[i32] }:$src1, -3:{ *:[i32] }) => (XOR:{ *:[i32] } GPR32:{ *:[i32] }:$src1)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::XOR,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 11: @[[LABEL]]
+// CHECK-NEXT:  // Label 12: @[[LABEL]]
 
 // The -3 is just to distinguish it from the 'not' case below and the other default op case above.
 def XOR : I<(outs GPR32:$dst), (ins Z:$src2, GPR32:$src1),
             [(set GPR32:$dst, (xor GPR32:$src1, -3))]>;
 
 //===- Test a simple pattern with a multiple default operands. ------------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 12*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 13*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_XOR,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckConstantInt, /*MI*/0, /*Op*/2, -4
 // CHECK-NEXT:    // (xor:{ *:[i32] } GPR32:{ *:[i32] }:$src1, -4:{ *:[i32] }) => (XORlike:{ *:[i32] } GPR32:{ *:[i32] }:$src1)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::XORlike,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddImm, /*InsnID*/0, /*Imm*/-1,
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 12: @[[LABEL]]
+// CHECK-NEXT:  // Label 13: @[[LABEL]]
 
 // The -4 is just to distinguish it from the other 'not' cases.
 def XORlike : I<(outs GPR32:$dst), (ins m1Z:$src2, GPR32:$src1),
                 [(set GPR32:$dst, (xor GPR32:$src1, -4))]>;
 
 //===- Test a simple pattern with multiple operands with defaults. --------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 13*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 14*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_XOR,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckConstantInt, /*MI*/0, /*Op*/2, -5,
 // CHECK-NEXT:    // (xor:{ *:[i32] } GPR32:{ *:[i32] }:$src1, -5:{ *:[i32] }) => (XORManyDefaults:{ *:[i32] } GPR32:{ *:[i32] }:$src1)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::XORManyDefaults,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddImm, /*InsnID*/0, /*Imm*/-1,
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 13: @[[LABEL]]
+// CHECK-NEXT:  // Label 14: @[[LABEL]]
 
 // The -5 is just to distinguish it from the other cases.
 def XORManyDefaults : I<(outs GPR32:$dst), (ins m1Z:$src3, Z:$src2, GPR32:$src1),
                         [(set GPR32:$dst, (xor GPR32:$src1, -5))]>;
 
 //===- Test a simple pattern with constant immediate operands. ------------===//
 //
 // This must precede the 3-register variants because constant immediates have
 // priority over register banks.
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 14*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 15*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/3,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_XOR,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Wm
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 2
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/2, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckConstantInt, /*MI*/0, /*Op*/2, -1,
 // CHECK-NEXT:    // (xor:{ *:[i32] } GPR32:{ *:[i32] }:$Wm, -1:{ *:[i32] }) => (ORN:{ *:[i32] } R0:{ *:[i32] }, GPR32:{ *:[i32] }:$Wm)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::ORN,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // Wm
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 14: @[[LABEL]]
+// CHECK-NEXT:  // Label 15: @[[LABEL]]
 
 def ORN : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2), []>;
 def : Pat<(not GPR32:$Wm), (ORN R0, GPR32:$Wm)>;
 
 //===- Test a COPY_TO_REGCLASS --------------------------------------------===//
 //
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 15*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 16*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_BITCAST,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] src1
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/1, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/1, /*RC*/MyTarget::FPR32RegClassID,
 // CHECK-NEXT:    // (bitconvert:{ *:[i32] } FPR32:{ *:[f32] }:$src1) => (COPY_TO_REGCLASS:{ *:[i32] } FPR32:{ *:[f32] }:$src1, GPR32:{ *:[i32] })
 // CHECK-NEXT:    GIR_MutateOpcode, /*InsnID*/0, /*RecycleInsnID*/0, /*Opcode*/TargetOpcode::COPY,
 // CHECK-NEXT:    GIR_ConstrainOperandRC, /*InsnID*/0, /*Op*/0, /*RC GPR32*/1,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 15: @[[LABEL]]
+// CHECK-NEXT:  // Label 16: @[[LABEL]]
 
 def : Pat<(i32 (bitconvert FPR32:$src1)),
           (COPY_TO_REGCLASS FPR32:$src1, GPR32)>;
 
 //===- Test a simple pattern with just a specific leaf immediate. ---------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 16*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 17*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_CONSTANT,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 1
 // CHECK-NEXT:    GIM_CheckLiteralInt, /*MI*/0, /*Op*/1, 1,
 // CHECK-NEXT:    // 1:{ *:[i32] }  =>  (MOV1:{ *:[i32] })
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOV1,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 16: @[[LABEL]]
+// CHECK-NEXT:  // Label 17: @[[LABEL]]
 
 def MOV1 : I<(outs GPR32:$dst), (ins), [(set GPR32:$dst, 1)]>;
 
 //===- Test a simple pattern with a leaf immediate and a predicate. -------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 17*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 18*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_CONSTANT,
 // CHECK-NEXT:    GIM_CheckI64ImmPredicate, /*MI*/0, /*Predicate*/GIPFP_I64_Predicate_simm8,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 1
 // CHECK-NEXT:    // No operand predicates
 // CHECK-NEXT:    // (imm:{ *:[i32] })<<P:Predicate_simm8>>:$imm => (MOVimm8:{ *:[i32] } (imm:{ *:[i32] }):$imm)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOVimm8,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_CopyConstantAsSImm, /*NewInsnID*/0, /*OldInsnID*/0, // imm
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 17: @[[LABEL]]
+// CHECK-NEXT:  // Label 18: @[[LABEL]]
 
 def simm8 : ImmLeaf<i32, [{ return isInt<8>(Imm); }]>;
 def MOVimm8 : I<(outs GPR32:$dst), (ins i32imm:$imm), [(set GPR32:$dst, simm8:$imm)]>;
 
 //===- Same again but use an IntImmLeaf. ----------------------------------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 18*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 19*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_CONSTANT,
 // CHECK-NEXT:    GIM_CheckAPIntImmPredicate, /*MI*/0, /*Predicate*/GIPFP_APInt_Predicate_simm9,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 1
 // CHECK-NEXT:    // No operand predicates
 // CHECK-NEXT:    // (imm:{ *:[i32] })<<P:Predicate_simm9>>:$imm =>  (MOVimm9:{ *:[i32] } (imm:{ *:[i32] }):$imm)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOVimm9,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_CopyConstantAsSImm, /*NewInsnID*/0, /*OldInsnID*/0, // imm
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 18: @[[LABEL]]
+// CHECK-NEXT:  // Label 19: @[[LABEL]]
 
 def simm9 : IntImmLeaf<i32, [{ return isInt<9>(Imm->getSExtValue()); }]>;
 def MOVimm9 : I<(outs GPR32:$dst), (ins i32imm:$imm), [(set GPR32:$dst, simm9:$imm)]>;
 
 //===- Test a simple pattern with just a leaf immediate. ------------------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 19*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 20*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_CONSTANT,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::GPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 1
 // CHECK-NEXT:    // No operand predicates
 // CHECK-NEXT:    // (imm:{ *:[i32] }):$imm =>  (MOVimm:{ *:[i32] } (imm:{ *:[i32] }):$imm)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOVimm,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_CopyConstantAsSImm, /*NewInsnID*/0, /*OldInsnID*/0, // imm
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 19: @[[LABEL]]
+// CHECK-NEXT:  // Label 20: @[[LABEL]]
 
 def MOVimm : I<(outs GPR32:$dst), (ins i32imm:$imm), [(set GPR32:$dst, imm:$imm)]>;
 
 //===- Test a simple pattern with a FP immediate and a predicate. ---------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 20*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 21*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_FCONSTANT,
 // CHECK-NEXT:    GIM_CheckAPFloatImmPredicate, /*MI*/0, /*Predicate*/GIPFP_APFloat_Predicate_fpimmz,
 // CHECK-NEXT:    // MIs[0] dst
 // CHECK-NEXT:    GIM_CheckType, /*MI*/0, /*Op*/0, /*Type*/GILLT_s32,
 // CHECK-NEXT:    GIM_CheckRegBankForClass, /*MI*/0, /*Op*/0, /*RC*/MyTarget::FPR32RegClassID,
 // CHECK-NEXT:    // MIs[0] Operand 1
 // CHECK-NEXT:    // No operand predicates
 // CHECK-NEXT:    // (fpimm:{ *:[f32] })<<P:Predicate_fpimmz>>:$imm =>  (MOVfpimmz:{ *:[f32] } (fpimm:{ *:[f32] }):$imm)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOVfpimmz,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_CopyFConstantAsFPImm, /*NewInsnID*/0, /*OldInsnID*/0, // imm
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 20: @[[LABEL]]
+// CHECK-NEXT:  // Label 21: @[[LABEL]]
 
 def fpimmz : FPImmLeaf<f32, [{ return Imm->isExactlyValue(0.0); }]>;
 def MOVfpimmz : I<(outs FPR32:$dst), (ins f32imm:$imm), [(set FPR32:$dst, fpimmz:$imm)]>;
 
 //===- Test a pattern with an MBB operand. --------------------------------===//
 
-// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 21*/ [[LABEL:[0-9]+]],
+// CHECK-NEXT:  GIM_Try, /*On fail goto*//*Label 22*/ [[LABEL:[0-9]+]],
 // CHECK-NEXT:    GIM_CheckNumOperands, /*MI*/0, /*Expected*/1,
 // CHECK-NEXT:    GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_BR,
 // CHECK-NEXT:    // MIs[0] target
 // CHECK-NEXT:    GIM_CheckIsMBB, /*MI*/0, /*Op*/0,
 // CHECK-NEXT:    // (br (bb:{ *:[Other] }):$target) => (BR (bb:{ *:[Other] }):$target)
 // CHECK-NEXT:    GIR_MutateOpcode, /*InsnID*/0, /*RecycleInsnID*/0, /*Opcode*/MyTarget::BR,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
-// CHECK-NEXT:  // Label 21: @[[LABEL]]
+// CHECK-NEXT:  // Label 22: @[[LABEL]]
 
 def BR : I<(outs), (ins unknown:$target),
             [(br bb:$target)]>;
 
 // CHECK-NEXT:    GIM_Reject,
 // CHECK-NEXT:  };
 // CHECK-NEXT:  if (executeMatchTable(*this, OutMIs, State, MatcherInfo, MatchTable0, TII, MRI, TRI, RBI, AvailableFeatures)) {
 // CHECK-NEXT:    return true;
 // CHECK-NEXT:  }

llvm/trunk/utils/TableGen/GlobalISelEmitter.cpp

class RuleMatcher {
   std::vector<std::unique_ptr<MatchAction>> Actions;
 
   typedef std::map<const InstructionMatcher *, unsigned>
       DefinedInsnVariablesMap;
   /// A map of instruction matchers to the local variables created by
   /// emitCaptureOpcodes().
   DefinedInsnVariablesMap InsnVariableIDs;
 
+  /// A map of named operands defined by the matchers that may be referenced by
+  /// the renderers.
+  StringMap<OperandMatcher *> DefinedOperands;
+
   /// ID for the next instruction variable defined with defineInsnVar()
   unsigned NextInsnVarID;
 
   std::vector<Record *> RequiredFeatures;
 
+  ArrayRef<SMLoc> SrcLoc;
+
 public:
-  RuleMatcher()
-      : Matchers(), Actions(), InsnVariableIDs(), NextInsnVarID(0) {}
+  RuleMatcher(ArrayRef<SMLoc> SrcLoc)
+      : Matchers(), Actions(), InsnVariableIDs(), DefinedOperands(),
+        NextInsnVarID(0), SrcLoc(SrcLoc) {}
   RuleMatcher(RuleMatcher &&Other) = default;
   RuleMatcher &operator=(RuleMatcher &&Other) = default;
 
   InstructionMatcher &addInstructionMatcher(StringRef SymbolicName);
   void addRequiredFeature(Record *Feature);
   const std::vector<Record *> &getRequiredFeatures() const;
 
   template <class Kind, class... Args> Kind &addAction(Args &&... args);
public:
   DefinedInsnVariablesMap::const_iterator defined_insn_vars_end() const {
     return InsnVariableIDs.end();
   }
   iterator_range<typename DefinedInsnVariablesMap::const_iterator>
   defined_insn_vars() const {
     return make_range(defined_insn_vars_begin(), defined_insn_vars_end());
   }
 
+  void defineOperand(StringRef SymbolicName, OperandMatcher &OM);
+
   const InstructionMatcher &getInstructionMatcher(StringRef SymbolicName) const;
+  const OperandMatcher &getOperandMatcher(StringRef Name) const;
 
   void emitCaptureOpcodes(MatchTable &Table);
 
   void emit(MatchTable &Table);
 
   /// Compare the priority of this object and B.
   ///
   /// Returns true if this object is more important than B.
private:
 
   /// Template instantiations should specialize this to return a string to use
   /// for the comment emitted when there are no predicates.
   std::string getNoPredicateComment() const;
 
 public:
   /// Construct a new operand predicate and add it to the matcher.
   template <class Kind, class... Args>
-  Kind &addPredicate(Args&&... args) {
+  Optional<Kind *> addPredicate(Args&&... args) {
     Predicates.emplace_back(
         llvm::make_unique<Kind>(std::forward<Args>(args)...));
-    return *static_cast<Kind *>(Predicates.back().get());
+    return static_cast<Kind *>(Predicates.back().get());
   }
 
   typename PredicateVec::const_iterator predicates_begin() const {
     return Predicates.begin();
   }
   typename PredicateVec::const_iterator predicates_end() const {
     return Predicates.end();
   }
public:
   /// This enum is used for RTTI and also defines the priority that is given to
   /// the predicate when generating the matcher code. Kinds with higher priority
   /// must be tested first.
   ///
   /// The relative priority of OPM_LLT, OPM_RegBank, and OPM_MBB do not matter
   /// but OPM_Int must have priority over OPM_RegBank since constant integers
   /// are represented by a virtual register defined by a G_CONSTANT instruction.
   enum PredicateKind {
+    OPM_Tie,
     OPM_ComplexPattern,
     OPM_IntrinsicID,
     OPM_Instruction,
     OPM_Int,
     OPM_LiteralInt,
     OPM_LLT,
     OPM_RegBank,
     OPM_MBB,
   };
 
 protected:
   PredicateKind Kind;
 
 public:
   OperandPredicateMatcher(PredicateKind Kind) : Kind(Kind) {}
   virtual ~OperandPredicateMatcher() {}
 
   PredicateKind getKind() const { return Kind; }
 
-  /// Return the OperandMatcher for the specified operand or nullptr if there
-  /// isn't one by that name in this operand predicate matcher.
-  ///
-  /// InstructionOperandMatcher is the only subclass that can return non-null
-  /// for this.
-  virtual Optional<const OperandMatcher *>
-  getOptionalOperand(StringRef SymbolicName) const {
-    assert(!SymbolicName.empty() && "Cannot lookup unnamed operand");
-    return None;
-  }
-
   /// Emit MatchTable opcodes to capture instructions into the MIs table.
   ///
   /// Only InstructionOperandMatcher needs to do anything for this method the
   /// rest just walk the tree.
   virtual void emitCaptureOpcodes(MatchTable &Table, RuleMatcher &Rule,
                                   unsigned InsnVarID, unsigned OpIdx) const {}
 
   /// Emit MatchTable opcodes that check the predicate for the given operand.

 };
 
 template <>
 std::string
 PredicateListMatcher<OperandPredicateMatcher>::getNoPredicateComment() const {
   return "No operand predicates";
 }
 
+/// Generates code to check that a register operand is defined by the same exact
+/// one as another.
+class SameOperandMatcher : public OperandPredicateMatcher {
+  std::string TiedTo;
+
+public:
+  SameOperandMatcher(StringRef TiedTo)
+      : OperandPredicateMatcher(OPM_Tie), TiedTo(TiedTo) {}
+
+  static bool classof(const OperandPredicateMatcher *P) {
+    return P->getKind() == OPM_Tie;
+  }
+
+  void emitPredicateOpcodes(MatchTable &Table, RuleMatcher &Rule,
+                            unsigned InsnVarID, unsigned OpIdx) const override;
+};
+
 /// Generates code to check that an operand is a particular LLT.
 class LLTOperandMatcher : public OperandPredicateMatcher {
 protected:
   LLTCodeGen Ty;
 
 public:
   static std::set<LLTCodeGen> KnownTypes;
 
public:
   }
   unsigned getOperandIndex() const { return OpIdx; }
 
   std::string getOperandExpr(unsigned InsnVarID) const {
     return "State.MIs[" + llvm::to_string(InsnVarID) + "]->getOperand(" +
            llvm::to_string(OpIdx) + ")";
   }
 
-  Optional<const OperandMatcher *>
-  getOptionalOperand(StringRef DesiredSymbolicName) const {
-    assert(!DesiredSymbolicName.empty() && "Cannot lookup unnamed operand");
-    if (DesiredSymbolicName == SymbolicName)
-      return this;
-    for (const auto &OP : predicates()) {
-      const auto &MaybeOperand = OP->getOptionalOperand(DesiredSymbolicName);
-      if (MaybeOperand.hasValue())
-        return MaybeOperand.getValue();
-    }
-    return None;
-  }
-
   InstructionMatcher &getInstructionMatcher() const { return Insn; }
 
   /// Emit MatchTable opcodes to capture instructions into the MIs table.
   void emitCaptureOpcodes(MatchTable &Table, RuleMatcher &Rule,
                           unsigned InsnVarID) const {
     for (const auto &Predicate : predicates())
       Predicate->emitCaptureOpcodes(Table, Rule, InsnVarID, OpIdx);
   }
return std::accumulate(
            const std::unique_ptr<OperandPredicateMatcher> &Predicate) {
           return A + Predicate->countRendererFns();
         });
   }
 
   unsigned getAllocatedTemporariesBaseID() const {
     return AllocatedTemporariesBaseID;
   }
+
+  bool isSameAsAnotherOperand() const {
+    for (const auto &Predicate : predicates())
+      if (isa<SameOperandMatcher>(Predicate))
+        return true;
+    return false;
+  }
 };
 
+// Specialize OperandMatcher::addPredicate() to refrain from adding redundant
+// predicates.
+template <>
+template <class Kind, class... Args>
+Optional<Kind *>
+PredicateListMatcher<OperandPredicateMatcher>::addPredicate(Args &&... args) {
+  if (static_cast<OperandMatcher *>(this)->isSameAsAnotherOperand())
+    return None;
+  Predicates.emplace_back(llvm::make_unique<Kind>(std::forward<Args>(args)...));
+  return static_cast<Kind *>(Predicates.back().get());
+}
+
 unsigned ComplexPatternOperandMatcher::getAllocatedTemporariesBaseID() const {
   return Operand.getAllocatedTemporariesBaseID();
 }
 
 /// Generates code to check a predicate on an instruction.
 ///
 /// Typical predicates include:
 /// * The opcode of the instruction is a particular value.

 /// Typical predicates include:
 /// * Has a specific opcode.
 /// * Has an nsw/nuw flag or doesn't.
 class InstructionMatcher
     : public PredicateListMatcher<InstructionPredicateMatcher> {
 protected:
   typedef std::vector<std::unique_ptr<OperandMatcher>> OperandVec;
 
+  RuleMatcher &Rule;
+
   /// The operands to match. All rendered operands must be present even if the
   /// condition is always true.
   OperandVec Operands;
 
   std::string SymbolicName;
 
 public:
-  InstructionMatcher(StringRef SymbolicName) : SymbolicName(SymbolicName) {}
+  InstructionMatcher(RuleMatcher &Rule, StringRef SymbolicName)
+      : Rule(Rule), SymbolicName(SymbolicName) {}
+
+  RuleMatcher &getRuleMatcher() const { return Rule; }
 
   /// Add an operand to the matcher.
   OperandMatcher &addOperand(unsigned OpIdx, const std::string &SymbolicName,
                              unsigned AllocatedTemporariesBaseID) {
     Operands.emplace_back(new OperandMatcher(*this, OpIdx, SymbolicName,
                                              AllocatedTemporariesBaseID));
+    if (!SymbolicName.empty())
+      Rule.defineOperand(SymbolicName, *Operands.back());
+
     return *Operands.back();
   }
 
   OperandMatcher &getOperand(unsigned OpIdx) {
     auto I = std::find_if(Operands.begin(), Operands.end(),
                           [&OpIdx](const std::unique_ptr<OperandMatcher> &X) {
                             return X->getOperandIndex() == OpIdx;
                           });
     if (I != Operands.end())
       return **I;
     llvm_unreachable("Failed to lookup operand");
   }
 
-  Optional<const OperandMatcher *>
-  getOptionalOperand(StringRef SymbolicName) const {
-    assert(!SymbolicName.empty() && "Cannot lookup unnamed operand");
-    for (const auto &Operand : Operands) {
-      const auto &OM = Operand->getOptionalOperand(SymbolicName);
-      if (OM.hasValue())
-        return OM.getValue();
-    }
-    return None;
-  }
-
-  const OperandMatcher &getOperand(StringRef SymbolicName) const {
-    Optional<const OperandMatcher *>OM = getOptionalOperand(SymbolicName);
-    if (OM.hasValue())
-      return *OM.getValue();
-    llvm_unreachable("Failed to lookup operand");
-  }
-
   StringRef getSymbolicName() const { return SymbolicName; }
   unsigned getNumOperands() const { return Operands.size(); }
   OperandVec::iterator operands_begin() { return Operands.begin(); }
   OperandVec::iterator operands_end() { return Operands.end(); }
   iterator_range<OperandVec::iterator> operands() {
     return make_range(operands_begin(), operands_end());
   }
   OperandVec::const_iterator operands_begin() const { return Operands.begin(); }

 /// the:
 ///   (G_ADD $src1, $src2)
 /// subpattern.
 class InstructionOperandMatcher : public OperandPredicateMatcher {
 protected:
   std::unique_ptr<InstructionMatcher> InsnMatcher;
 
 public:
-  InstructionOperandMatcher(StringRef SymbolicName)
+  InstructionOperandMatcher(RuleMatcher &Rule, StringRef SymbolicName)
       : OperandPredicateMatcher(OPM_Instruction),
-        InsnMatcher(new InstructionMatcher(SymbolicName)) {}
+        InsnMatcher(new InstructionMatcher(Rule, SymbolicName)) {}
 
   static bool classof(const OperandPredicateMatcher *P) {
     return P->getKind() == OPM_Instruction;
   }
 
   InstructionMatcher &getInsnMatcher() const { return *InsnMatcher; }
 
-  Optional<const OperandMatcher *>
-  getOptionalOperand(StringRef SymbolicName) const override {
-    assert(!SymbolicName.empty() && "Cannot lookup unnamed operand");
-    return InsnMatcher->getOptionalOperand(SymbolicName);
-  }
-
   void emitCaptureOpcodes(MatchTable &Table, RuleMatcher &Rule,
                           unsigned InsnID, unsigned OpIdx) const override {
     unsigned InsnVarID = Rule.defineInsnVar(Table, *InsnMatcher, InsnID, OpIdx);
     InsnMatcher->emitCaptureOpcodes(Table, Rule, InsnVarID);
   }
 
   void emitPredicateOpcodes(MatchTable &Table, RuleMatcher &Rule,
                             unsigned InsnVarID_,
public:
 
   static bool classof(const OperandRenderer *R) {
     return R->getKind() == OR_Copy;
   }
 
   const StringRef getSymbolicName() const { return SymbolicName; }
 
   void emitRenderOpcodes(MatchTable &Table, RuleMatcher &Rule) const override {
-    const OperandMatcher &Operand = Matched.getOperand(SymbolicName);
+    const OperandMatcher &Operand = Rule.getOperandMatcher(SymbolicName);
     unsigned OldInsnVarID = Rule.getInsnVarID(Operand.getInstructionMatcher());
     Table << MatchTable::Opcode("GIR_Copy") << MatchTable::Comment("NewInsnID")
           << MatchTable::IntValue(NewInsnID) << MatchTable::Comment("OldInsnID")
           << MatchTable::IntValue(OldInsnVarID) << MatchTable::Comment("OpIdx")
           << MatchTable::IntValue(Operand.getOperandIndex())
           << MatchTable::Comment(SymbolicName) << MatchTable::LineBreak;
   }
 };
public:
 
   static bool classof(const OperandRenderer *R) {
     return R->getKind() == OR_CopySubReg;
   }
 
   const StringRef getSymbolicName() const { return SymbolicName; }
 
   void emitRenderOpcodes(MatchTable &Table, RuleMatcher &Rule) const override {
-    const OperandMatcher &Operand = Matched.getOperand(SymbolicName);
+    const OperandMatcher &Operand = Rule.getOperandMatcher(SymbolicName);
     unsigned OldInsnVarID = Rule.getInsnVarID(Operand.getInstructionMatcher());
     Table << MatchTable::Opcode("GIR_CopySubReg")
           << MatchTable::Comment("NewInsnID") << MatchTable::IntValue(NewInsnID)
           << MatchTable::Comment("OldInsnID")
           << MatchTable::IntValue(OldInsnVarID) << MatchTable::Comment("OpIdx")
           << MatchTable::IntValue(Operand.getOperandIndex())
           << MatchTable::Comment("SubRegIdx")
           << MatchTable::IntValue(SubReg->EnumValue)

 class BuildMIAction : public MatchAction {
 private:
   unsigned InsnID;
   const CodeGenInstruction *I;
   const InstructionMatcher &Matched;
   std::vector<std::unique_ptr<OperandRenderer>> OperandRenderers;
 
   /// True if the instruction can be built solely by mutating the opcode.
-  bool canMutate() const {
+  bool canMutate(RuleMatcher &Rule) const {
     if (OperandRenderers.size() != Matched.getNumOperands())
       return false;
 
     for (const auto &Renderer : enumerate(OperandRenderers)) {
       if (const auto *Copy = dyn_cast<CopyRenderer>(&*Renderer.value())) {
-        const OperandMatcher &OM = Matched.getOperand(Copy->getSymbolicName());
+        const OperandMatcher &OM = Rule.getOperandMatcher(Copy->getSymbolicName());
         if (&Matched != &OM.getInstructionMatcher() ||
             OM.getOperandIndex() != Renderer.index())
           return false;
       } else
         return false;
     }
 
     return true;
   }
 
 public:
   BuildMIAction(unsigned InsnID, const CodeGenInstruction *I,
                 const InstructionMatcher &Matched)
       : InsnID(InsnID), I(I), Matched(Matched) {}
 
   template <class Kind, class... Args>
   Kind &addRenderer(Args&&... args) {
     OperandRenderers.emplace_back(
         llvm::make_unique<Kind>(std::forward<Args>(args)...));
     return *static_cast<Kind *>(OperandRenderers.back().get());
   }
 
   void emitActionOpcodes(MatchTable &Table, RuleMatcher &Rule,
                          unsigned RecycleInsnID) const override {
-    if (canMutate()) {
+    if (canMutate(Rule)) {
       Table << MatchTable::Opcode("GIR_MutateOpcode")
             << MatchTable::Comment("InsnID") << MatchTable::IntValue(InsnID)
             << MatchTable::Comment("RecycleInsnID")
             << MatchTable::IntValue(RecycleInsnID)
             << MatchTable::Comment("Opcode")
             << MatchTable::NamedValue(I->Namespace, I->TheDef->getName())
             << MatchTable::LineBreak;
 
Table << MatchTable::Opcode("GIR_ConstrainOperandRC")
           << MatchTable::Comment("InsnID") << MatchTable::IntValue(InsnID)
           << MatchTable::Comment("Op") << MatchTable::IntValue(OpIdx)
           << MatchTable::Comment("RC " + RC.getName())
           << MatchTable::IntValue(RC.EnumValue) << MatchTable::LineBreak;
   }
 };
 
 InstructionMatcher &RuleMatcher::addInstructionMatcher(StringRef SymbolicName) {
-  Matchers.emplace_back(new InstructionMatcher(SymbolicName));
+  Matchers.emplace_back(new InstructionMatcher(*this, SymbolicName));
   return *Matchers.back();
 }
 
 void RuleMatcher::addRequiredFeature(Record *Feature) {
   RequiredFeatures.push_back(Feature);
 }
 
 const std::vector<Record *> &RuleMatcher::getRequiredFeatures() const {

 
 unsigned RuleMatcher::getInsnVarID(const InstructionMatcher &InsnMatcher) const {
   const auto &I = InsnVariableIDs.find(&InsnMatcher);
   if (I != InsnVariableIDs.end())
     return I->second;
   llvm_unreachable("Matched Insn was not captured in a local variable");
 }
 
+void RuleMatcher::defineOperand(StringRef SymbolicName, OperandMatcher &OM) {
+  if (DefinedOperands.find(SymbolicName) == DefinedOperands.end()) {
+    DefinedOperands[SymbolicName] = &OM;
+    return;
+  }
+
+  // If the operand is already defined, then we must ensure both references in
+  // the matcher have the exact same node.
+  OM.addPredicate<SameOperandMatcher>(OM.getSymbolicName());
+}
+
 const InstructionMatcher &
 RuleMatcher::getInstructionMatcher(StringRef SymbolicName) const {
   for (const auto &I : InsnVariableIDs)
     if (I.first->getSymbolicName() == SymbolicName)
       return *I.first;
   llvm_unreachable(
       ("Failed to lookup instruction " + SymbolicName).str().c_str());
 }
 
+const OperandMatcher &
+RuleMatcher::getOperandMatcher(StringRef Name) const {
+  const auto &I = DefinedOperands.find(Name);
+
+  if (I == DefinedOperands.end())
+    PrintFatalError(SrcLoc, "Operand " + Name + " was not declared in matcher");
+
+  return *I->second;
+}
+
 /// Emit MatchTable opcodes to check the shape of the match and capture
 /// instructions into local variables.
 void RuleMatcher::emitCaptureOpcodes(MatchTable &Table) {
   assert(Matchers.size() == 1 && "Cannot handle multi-root matchers yet");
   unsigned InsnVarID = implicitlyDefineInsnVar(*Matchers.front());
   Matchers.front()->emitCaptureOpcodes(Table, *this, InsnVarID);
 }
 
bool OperandPredicateMatcher::isHigherPriorityThan(
   if (AOM && AIsConstantInsn && (B.Kind == OPM_Int || B.Kind == OPM_LiteralInt))
     return false;
   if (BOM && BIsConstantInsn && (Kind == OPM_Int || Kind == OPM_LiteralInt))
     return true;
 
   return Kind < B.Kind;
 }
 
+void SameOperandMatcher::emitPredicateOpcodes(MatchTable &Table,
+                                              RuleMatcher &Rule,
+                                              unsigned InsnVarID,
+                                              unsigned OpIdx) const {
+  const OperandMatcher &OtherOM = Rule.getOperandMatcher(TiedTo);
+  unsigned OtherInsnVarID = Rule.getInsnVarID(OtherOM.getInstructionMatcher());
+
+  Table << MatchTable::Opcode("GIM_CheckIsSameOperand")
+        << MatchTable::Comment("MI") << MatchTable::IntValue(InsnVarID)
+        << MatchTable::Comment("OpIdx") << MatchTable::IntValue(OpIdx)
+        << MatchTable::Comment("OtherMI")
+        << MatchTable::IntValue(OtherInsnVarID)
+        << MatchTable::Comment("OtherOpIdx")
+        << MatchTable::IntValue(OtherOM.getOperandIndex())
+        << MatchTable::LineBreak;
+}
+
 //===- GlobalISelEmitter class --------------------------------------------===//
 
 class GlobalISelEmitter {
 public:
   explicit GlobalISelEmitter(RecordKeeper &RK);
   void run(raw_ostream &OS);
 
 private:
createAndImportSelDAGMatcher(InstructionMatcher &InsnMatcher,
                                const TreePatternNode *Src,
                                unsigned &TempOpIdx) const;
   Error importChildMatcher(InstructionMatcher &InsnMatcher,
                            const TreePatternNode *SrcChild, unsigned OpIdx,
                            unsigned &TempOpIdx) const;
   Expected<BuildMIAction &>
   createAndImportInstructionRenderer(RuleMatcher &M, const TreePatternNode *Dst,
                                      const InstructionMatcher &InsnMatcher);
-  Error importExplicitUseRenderer(BuildMIAction &DstMIBuilder,
+  Error importExplicitUseRenderer(RuleMatcher &Rule,
+                                  BuildMIAction &DstMIBuilder,
                                   TreePatternNode *DstChild,
                                   const InstructionMatcher &InsnMatcher) const;
   Error importDefaultOperandRenderers(BuildMIAction &DstMIBuilder,
                                       DagInit *DefaultOps) const;
   Error
   importImplicitDefRenderers(BuildMIAction &DstMIBuilder,
                              const std::vector<Record *> &ImplicitDefs) const;
 
for (const auto &Predicate : Src->getPredicateFns()) {
 
     return failedImport("Src pattern child has predicate (" +
                         explainPredicates(Src) + ")");
   }
 
   if (Src->isLeaf()) {
     Init *SrcInit = Src->getLeafValue();
     if (IntInit *SrcIntInit = dyn_cast<IntInit>(SrcInit)) {
-      OperandMatcher &OM = InsnMatcher.addOperand(OpIdx++, "", TempOpIdx);
+      OperandMatcher &OM =
+          InsnMatcher.addOperand(OpIdx++, Src->getName(), TempOpIdx);
       OM.addPredicate<LiteralIntOperandMatcher>(SrcIntInit->getValue());
     } else
       return failedImport(
           "Unable to deduce gMIR opcode to handle Src (which is a leaf)");
   } else {
     assert(SrcGIOrNull &&
            "Expected to have already found an equivalent Instruction");
     if (SrcGIOrNull->TheDef->getName() == "G_CONSTANT" ||

 }
 
 Error GlobalISelEmitter::importChildMatcher(InstructionMatcher &InsnMatcher,
                                             const TreePatternNode *SrcChild,
                                             unsigned OpIdx,
                                             unsigned &TempOpIdx) const {
   OperandMatcher &OM =
       InsnMatcher.addOperand(OpIdx, SrcChild->getName(), TempOpIdx);
+  if (OM.isSameAsAnotherOperand())
+    return Error::success();
 
   ArrayRef<TypeSetByHwMode> ChildTypes = SrcChild->getExtTypes();
   if (ChildTypes.size() != 1)
     return failedImport("Src pattern child has multiple results");
 
   // Check MBB's before the type check since they are not a known type.
   if (!SrcChild->isLeaf()) {
     if (SrcChild->getOperator()->isSubClassOf("SDNode")) {
Error GlobalISelEmitter::importChildMatcher(InstructionMatcher &InsnMatcher,
   if (ChildTypes.front().isMachineValueType())
     OpTyOrNone = MVTToLLT(ChildTypes.front().getMachineValueType().SimpleTy);
   if (!OpTyOrNone)
     return failedImport("Src operand has an unsupported type (" + to_string(*SrcChild) + ")");
   OM.addPredicate<LLTOperandMatcher>(*OpTyOrNone);
 
   // Check for nested instructions.
   if (!SrcChild->isLeaf()) {
+    auto MaybeInsnOperand = OM.addPredicate<InstructionOperandMatcher>(
+        InsnMatcher.getRuleMatcher(), SrcChild->getName());
+    if (!MaybeInsnOperand.hasValue()) {
+      // This isn't strictly true. If the user were to provide exactly the same
+      // matchers as the original operand then we could allow it. However, it's
+      // simpler to not permit the redundant specification.
+      return failedImport("Nested instruction cannot be the same as another operand");
+    }
+
     // Map the node to a gMIR instruction.
-    InstructionOperandMatcher &InsnOperand =
-        OM.addPredicate<InstructionOperandMatcher>(SrcChild->getName());
+    InstructionOperandMatcher &InsnOperand = **MaybeInsnOperand;
     auto InsnMatcherOrError = createAndImportSelDAGMatcher(
         InsnOperand.getInsnMatcher(), SrcChild, TempOpIdx);
     if (auto Error = InsnMatcherOrError.takeError())
       return Error;
 
     return Error::success();
   }
 
if (auto *ChildDefInit = dyn_cast<DefInit>(SrcChild->getLeafValue())) {
     return failedImport(
         "Src pattern child def is an unsupported tablegen class");
   }
 
   return failedImport("Src pattern child is an unsupported kind");
 }
 
 Error GlobalISelEmitter::importExplicitUseRenderer(
-    BuildMIAction &DstMIBuilder, TreePatternNode *DstChild,
+    RuleMatcher &Rule, BuildMIAction &DstMIBuilder, TreePatternNode *DstChild,
     const InstructionMatcher &InsnMatcher) const {
   if (DstChild->getTransformFn() != nullptr) {
     return failedImport("Dst pattern child has transform fn " +
                         DstChild->getTransformFn()->getName());
   }
 
   if (!DstChild->isLeaf()) {
     // We accept 'bb' here. It's an operator because BasicBlockSDNode isn't
if (auto *ChildDefInit = dyn_cast<DefInit>(DstChild->getLeafValue())) {
     }
 
     if (ChildRec->isSubClassOf("ComplexPattern")) {
       const auto &ComplexPattern = ComplexPatternEquivs.find(ChildRec);
       if (ComplexPattern == ComplexPatternEquivs.end())
         return failedImport(
             "SelectionDAG ComplexPattern not mapped to GlobalISel");
 
-      const OperandMatcher &OM = InsnMatcher.getOperand(DstChild->getName());
+      const OperandMatcher &OM = Rule.getOperandMatcher(DstChild->getName());
       DstMIBuilder.addRenderer<RenderComplexPatternOperand>(
           0, *ComplexPattern->second, DstChild->getName(),
           OM.getAllocatedTemporariesBaseID());
       return Error::success();
     }
 
     if (ChildRec->isSubClassOf("SDNodeXForm"))
       return failedImport("Dst pattern child def is an unsupported tablegen "
if (DstIOperand.Rec->isSubClassOf("OperandWithDefaultOps")) {
       DagInit *DefaultOps = DstIOperand.Rec->getValueAsDag("DefaultOps");
       if (auto Error = importDefaultOperandRenderers(DstMIBuilder, DefaultOps))
         return std::move(Error);
       ++NumDefaultOps;
       continue;
     }
 
     if (auto Error = importExplicitUseRenderer(
-            DstMIBuilder, Dst->getChild(Child), InsnMatcher))
+            M, DstMIBuilder, Dst->getChild(Child), InsnMatcher))
       return std::move(Error);
     ++Child;
   }
 
   if (NumDefaultOps + ExpectedDstINumUses != DstINumUses)
     return failedImport("Expected " + llvm::to_string(DstINumUses) +
                         " used operands but found " +
                         llvm::to_string(ExpectedDstINumUses) +
Error GlobalISelEmitter::importImplicitDefRenderers(
     const std::vector<Record *> &ImplicitDefs) const {
   if (!ImplicitDefs.empty())
     return failedImport("Pattern defines a physical register");
   return Error::success();
 }
 
 Expected<RuleMatcher> GlobalISelEmitter::runOnPattern(const PatternToMatch &P) {
   // Keep track of the matchers and actions to emit.
-  RuleMatcher M;
+  RuleMatcher M(P.getSrcRecord()->getLoc());
   M.addAction<DebugCommentAction>(P);
 
   if (auto Error = importRulePredicates(M, P.getPredicates()))
     return std::move(Error);
 
   // Next, analyze the pattern operators.
   TreePatternNode *Src = P.getSrcPattern();
   TreePatternNode *Dst = P.getDstPattern();
if (RCDef) {
       // We need to replace the def and all its uses with the specified
       // operand. However, we must also insert COPY's wherever needed.
       // For now, emit a copy and let the register allocator clean up.
       auto &DstI = Target.getInstruction(RK.getDef("COPY"));
       const auto &DstIOperand = DstI.Operands[0];
 
       OperandMatcher &OM0 = InsnMatcher.getOperand(0);
       OM0.setSymbolicName(DstIOperand.Name);
+      M.defineOperand(OM0.getSymbolicName(), OM0);
       OM0.addPredicate<RegisterBankOperandMatcher>(RC);
 
       auto &DstMIBuilder = M.addAction<BuildMIAction>(0, &DstI, InsnMatcher);
       DstMIBuilder.addRenderer<CopyRenderer>(0, InsnMatcher, DstIOperand.Name);
       DstMIBuilder.addRenderer<CopyRenderer>(0, InsnMatcher, Dst->getName());
       M.addAction<ConstrainOperandToRegClassAction>(0, 0, RC);
 
       // We're done with this pattern!  It's eligible for GISel emission; return
for (const TypeSetByHwMode &VTy : Src->getExtTypes()) {
     } else if (DstIOpRec->isSubClassOf("RegisterOperand"))
       DstIOpRec = DstIOpRec->getValueAsDef("RegClass");
     else if (!DstIOpRec->isSubClassOf("RegisterClass"))
       return failedImport("Dst MI def isn't a register class" +
                           to_string(*Dst));
 
     OperandMatcher &OM = InsnMatcher.getOperand(OpIdx);
     OM.setSymbolicName(DstIOperand.Name);
+    M.defineOperand(OM.getSymbolicName(), OM);
     OM.addPredicate<RegisterBankOperandMatcher>(
         Target.getRegisterClass(DstIOpRec));
     ++OpIdx;
   }
 
   auto DstMIBuilderOrError =
       createAndImportInstructionRenderer(M, Dst, InsnMatcher);
   if (auto Error = DstMIBuilderOrError.takeError())