Remove target opcode

Author: MacDue

llvm/include/llvm/Support/TargetOpcodes.def

@@ -225,9 +225,6 @@ HANDLE_TARGET_OPCODE(ICALL_BRANCH_FUNNEL)
 /// Represents a use of the operand but generates no code.
 HANDLE_TARGET_OPCODE(FAKE_USE)
 
-/// Represents a point in a chain optimizations cannot remove.
-HANDLE_TARGET_OPCODE(CHAIN_BARRIER)
-
 // This is a fence with the singlethread scope. It represents a compiler memory
 // barrier, but does not correspond to any generated instruction.
 HANDLE_TARGET_OPCODE(MEMBARRIER)

llvm/include/llvm/Target/Target.td

@@ -1442,17 +1442,6 @@ def FAKE_USE : StandardPseudoInstruction {
 }
 
 
-def CHAIN_BARRIER : StandardPseudoInstruction {
-  // An instruction that takes a chain to mark that optimizations should not
-  // optimize any users of a chain that contains a CHAIN_BARRIER use a new chain
-  // from a point earlier than the CHAIN_BARRIER.
-  let OutOperandList = (outs);
-  let InOperandList = (ins variable_ops);
-  let AsmString = "CHAIN_BARRIER";
-  let hasSideEffects = 0;
-  let isMeta = true;
-}
-
 def PATCHABLE_OP : StandardPseudoInstruction {
   let OutOperandList = (outs);
   let InOperandList = (ins variable_ops);

llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

@@ -2506,9 +2506,11 @@ void SelectionDAGISel::Select_FAKE_USE(SDNode *N) {
   CurDAG->SelectNodeTo(N, TargetOpcode::FAKE_USE, N->getValueType(0),
                        N->getOperand(1), N->getOperand(0));
 }
+
 void SelectionDAGISel::Select_CHAIN_BARRIER(SDNode *N) {
-  CurDAG->SelectNodeTo(N, TargetOpcode::CHAIN_BARRIER, N->getValueType(0),
-                       N->getOperand(0));
+  // CHAIN_BARRIER exists only for SDAG. Remove it before lowering to MIs.
+  CurDAG->ReplaceAllUsesWith(SDValue(N, 0), N->getOperand(0));
+  CurDAG->RemoveDeadNode(N);
 }
 
 void SelectionDAGISel::Select_FREEZE(SDNode *N) {

llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir

@@ -70,11 +70,11 @@
 # DEBUG-NEXT: .. the first uncovered type index: 1, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 #
-# DEBUG-NEXT: G_ABDS (opcode {{[0-9]+}}): 1 type index, 0 imm indices
+# DEBUG-NEXT: G_ABDS (opcode 65): 1 type index, 0 imm indices
 # DEBUG-NEXT:.. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT:.. imm index coverage check SKIPPED: no rules defined
 #
-# DEBUG-NEXT:G_ABDU (opcode {{[0-9]+}}): 1 type index, 0 imm indices
+# DEBUG-NEXT:G_ABDU (opcode 66): 1 type index, 0 imm indices
 # DEBUG-NEXT:.. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT:.. imm index coverage check SKIPPED: no rules defined
 #

llvm/test/CodeGen/RISCV/GlobalISel/legalizer-info-validation.mir

@@ -72,11 +72,11 @@
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 #
-# DEBUG-NEXT: G_ABDS (opcode {{[0-9]+}}): 1 type index, 0 imm indices
+# DEBUG-NEXT: G_ABDS (opcode 65): 1 type index, 0 imm indices
 # DEBUG-NEXT:.. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT:.. imm index coverage check SKIPPED: no rules defined
 #
-# DEBUG-NEXT:G_ABDU (opcode {{[0-9]+}}): 1 type index, 0 imm indices
+# DEBUG-NEXT:G_ABDU (opcode 66): 1 type index, 0 imm indices
 # DEBUG-NEXT:.. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT:.. imm index coverage check SKIPPED: no rules defined
 #
@@ -579,7 +579,7 @@
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: G_FMINIMUM (opcode {{[0-9]+}}): 1 type index
-# DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
+# DEBUG-NEXT: .. opcode 212 is aliased to 213
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: G_FMAXIMUM (opcode {{[0-9]+}}): 1 type index