[RISCV][GISel] Select trap and debugtrap.

[topperc]

No description provided.

[llvmbot]

@llvm/pr-subscribers-llvm-globalisel

@llvm/pr-subscribers-backend-risc-v

Author: Craig Topper (topperc)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/73171.diff

2 Files Affected:

• (modified) llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp (+25)
• (added) llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/trap.mir (+34)

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
index 3c72269d1e00c2f..791ce7a855d9888 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
@@ -72,6 +72,8 @@ class RISCVInstructionSelector : public InstructionSelector {
                     MachineRegisterInfo &MRI) const;
   bool selectFPCompare(MachineInstr &MI, MachineIRBuilder &MIB,
                        MachineRegisterInfo &MRI) const;
+  bool selectIntrinsicWithSideEffects(MachineInstr &I, MachineIRBuilder &MIB,
+                                      MachineRegisterInfo &MRI);
 
   ComplexRendererFns selectShiftMask(MachineOperand &Root) const;
   ComplexRendererFns selectAddrRegImm(MachineOperand &Root) const;
@@ -564,6 +566,8 @@ bool RISCVInstructionSelector::select(MachineInstr &MI) {
     return selectSelect(MI, MIB, MRI);
   case TargetOpcode::G_FCMP:
     return selectFPCompare(MI, MIB, MRI);
+  case TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS:
+    return selectIntrinsicWithSideEffects(MI, MIB, MRI);
   default:
     return false;
   }
@@ -1099,6 +1103,27 @@ bool RISCVInstructionSelector::selectFPCompare(MachineInstr &MI,
   return true;
 }
 
+bool RISCVInstructionSelector::selectIntrinsicWithSideEffects(
+    MachineInstr &I, MachineIRBuilder &MIB, MachineRegisterInfo &MRI) {
+  // Find the intrinsic ID.
+  unsigned IntrinID = cast<GIntrinsic>(I).getIntrinsicID();
+
+  // Select the instruction.
+  switch (IntrinID) {
+  default:
+    return false;
+  case Intrinsic::trap:
+    MIB.buildInstr(RISCV::UNIMP, {}, {});
+    break;
+  case Intrinsic::debugtrap:
+    MIB.buildInstr(RISCV::EBREAK, {}, {});
+    break;
+  }
+
+  I.eraseFromParent();
+  return true;
+}
+
 namespace llvm {
 InstructionSelector *
 createRISCVInstructionSelector(const RISCVTargetMachine &TM,
diff --git a/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/trap.mir b/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/trap.mir
new file mode 100644
index 000000000000000..11789a030e6fac0
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/trap.mir
@@ -0,0 +1,34 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=riscv32 -run-pass=instruction-select -simplify-mir \
+# RUN:   -verify-machineinstrs %s -o - | FileCheck %s
+# RUN: llc -mtriple=riscv64 -run-pass=instruction-select -simplify-mir \
+# RUN:   -verify-machineinstrs %s -o - | FileCheck %s
+
+---
+name:            test_trap
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1:
+    ; CHECK-LABEL: name: test_trap
+    ; CHECK: UNIMP
+    ; CHECK-NEXT: PseudoRET
+    G_INTRINSIC_W_SIDE_EFFECTS intrinsic(@llvm.trap)
+    PseudoRET
+
+...
+---
+name:            test_debugtrap
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1:
+    ; CHECK-LABEL: name: test_debugtrap
+    ; CHECK: EBREAK
+    ; CHECK-NEXT: PseudoRET
+    G_INTRINSIC_W_SIDE_EFFECTS intrinsic(@llvm.debugtrap)
+    PseudoRET
+
+...

[michaelmaitland]

LGTM with one minor comment.

[michaelmaitland]

assert (TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS);

[topperc]

Doesn't the cast to GIntrinsic already take care of that?

[michaelmaitland]

I think it will pass in the G_INTRINSIC, G_INTRINSIC_CONVERGENT, and G_INTRINSIC_CONVERGENT_W_WIDE_EFFECTS too, but it shouldn't.