[RISCV][GISEL] Legalize G_PTRMASK

G_PTRMASK is custom legalized by using G_PTRTOINT on the pointer, using a
G_AND to calculate the mask, and converted back to pointer using G_PTRTOINT.

Author: michaelmaitland

llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp

@@ -147,6 +147,8 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST) {
 
   getActionDefinitionsBuilder(G_PTR_ADD).legalFor({{p0, sXLen}});
 
+  getActionDefinitionsBuilder(G_PTRMASK).customFor({{p0, sXLen}});
+
   getActionDefinitionsBuilder(G_PTRTOINT)
       .legalFor({{sXLen, p0}})
       .clampScalar(0, sXLen, sXLen);
@@ -288,6 +290,25 @@ bool RISCVLegalizerInfo::legalizeShlAshrLshr(
   return true;
 }
 
+bool RISCVLegalizerInfo::legalizePtrMask(MachineInstr &MI,
+                                         MachineIRBuilder &MIRBuilder,
+                                         GISelChangeObserver &Observer) const {
+  assert(MI.getOpcode() == TargetOpcode::G_PTRMASK);
+
+  MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
+  Register Tmp1 =
+      MRI.createGenericVirtualRegister(MRI.getType(MI.getOperand(2).getReg()));
+  Register Tmp2 =
+      MRI.createGenericVirtualRegister(MRI.getType(MI.getOperand(2).getReg()));
+  MIRBuilder.buildPtrToInt(Tmp1, MI.getOperand(1).getReg());
+  MIRBuilder.buildAnd(Tmp2, Tmp1, MI.getOperand(2).getReg());
+  MIRBuilder.buildIntToPtr(MI.getOperand(0).getReg(), Tmp2);
+
+  Observer.erasingInstr(MI);
+  MI.eraseFromParent();
+  return true;
+}
+
 bool RISCVLegalizerInfo::legalizeCustom(LegalizerHelper &Helper,
                                         MachineInstr &MI) const {
   MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
@@ -309,6 +330,8 @@ bool RISCVLegalizerInfo::legalizeCustom(LegalizerHelper &Helper,
     return Helper.lower(MI, 0, /* Unused hint type */ LLT()) ==
            LegalizerHelper::Legalized;
   }
+  case TargetOpcode::G_PTRMASK:
+    return legalizePtrMask(MI, MIRBuilder, Observer);
   }
 
   llvm_unreachable("expected switch to return");

llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.h

@@ -31,6 +31,9 @@ class RISCVLegalizerInfo : public LegalizerInfo {
 private:
   bool legalizeShlAshrLshr(MachineInstr &MI, MachineIRBuilder &MIRBuilder,
                            GISelChangeObserver &Observer) const;
+
+  bool legalizePtrMask(MachineInstr &MI, MachineIRBuilder &MIRBuilder,
+                       GISelChangeObserver &Observer) const;
 };
 } // end namespace llvm
 #endif

llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-ptrmask-rv32.mir

@@ -0,0 +1,24 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=riscv32 -run-pass=legalizer -verify-machineinstrs %s -o - | FileCheck %s
+
+---
+name:            ptrmask_p0_s32
+body:             |
+  bb.0:
+    liveins: $x10, $x11
+    ; CHECK-LABEL: name: ptrmask_p0_s32
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(p0) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $x11
+    ; CHECK-NEXT: [[PTRTOINT:%[0-9]+]]:_(s32) = G_PTRTOINT [[COPY]](p0)
+    ; CHECK-NEXT: [[AND:%[0-9]+]]:_(s32) = G_AND [[PTRTOINT]], [[COPY1]]
+    ; CHECK-NEXT: [[INTTOPTR:%[0-9]+]]:_(p0) = G_INTTOPTR [[AND]](s32)
+    ; CHECK-NEXT: $x10 = COPY [[INTTOPTR]](p0)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:_(p0) = COPY $x10
+    %1:_(s32) = COPY $x11
+    %2:_(p0) = G_PTRMASK %0(p0), %1(s32)
+    $x10 = COPY %2(p0)
+    PseudoRET implicit $x10
+...

llvm/test/CodeGen/RISCV/GlobalISel/legalizer/legalize-ptrmask-rv64.mir

@@ -0,0 +1,24 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=riscv64 -run-pass=legalizer -verify-machineinstrs %s -o - | FileCheck %s
+
+---
+name:            ptrmask_p0_s64
+body:             |
+  bb.0:
+    liveins: $x10, $x11
+    ; CHECK-LABEL: name: ptrmask_p0_s64
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(p0) = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $x11
+    ; CHECK-NEXT: [[PTRTOINT:%[0-9]+]]:_(s64) = G_PTRTOINT [[COPY]](p0)
+    ; CHECK-NEXT: [[AND:%[0-9]+]]:_(s64) = G_AND [[PTRTOINT]], [[COPY1]]
+    ; CHECK-NEXT: [[INTTOPTR:%[0-9]+]]:_(p0) = G_INTTOPTR [[AND]](s64)
+    ; CHECK-NEXT: $x10 = COPY [[INTTOPTR]](p0)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:_(p0) = COPY $x10
+    %1:_(s64) = COPY $x11
+    %2:_(p0) = G_PTRMASK %0(p0), %1(s64)
+    $x10 = COPY %2(p0)
+    PseudoRET implicit $x10
+...