[ARM] GlobalISel: Select shifts

Unfortunately TableGen doesn't handle this yet:
Unable to deduce gMIR opcode to handle Src (which is a leaf).

Just add some temporary hand-written code to generate the proper MOVsr.

llvm-svn: 315071

lib/Target/ARM/ARMInstructionSelector.cpp

@@ -59,6 +59,7 @@ private:
 
   bool selectGlobal(MachineInstrBuilder &MIB, MachineRegisterInfo &MRI) const;
   bool selectSelect(MachineInstrBuilder &MIB, MachineRegisterInfo &MRI) const;
+  bool selectShift(unsigned ShiftOpc, MachineInstrBuilder &MIB) const;
 
   // Check if the types match and both operands have the expected size and
   // register bank.
@@ -640,6 +641,14 @@ bool ARMInstructionSelector::selectSelect(MachineInstrBuilder &MIB,
   return true;
 }
 
+bool ARMInstructionSelector::selectShift(unsigned ShiftOpc,
+                                         MachineInstrBuilder &MIB) const {
+  MIB->setDesc(TII.get(ARM::MOVsr));
+  MIB.addImm(ShiftOpc);
+  MIB.add(predOps(ARMCC::AL)).add(condCodeOp());
+  return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
+}
+
 bool ARMInstructionSelector::select(MachineInstr &I) const {
   assert(I.getParent() && "Instruction should be in a basic block!");
   assert(I.getParent()->getParent() && "Instruction should be in a function!");
@@ -766,6 +775,13 @@ bool ARMInstructionSelector::select(MachineInstr &I) const {
                         ARM::FPRRegBankID, Size);
     return selectCmp(Helper, MIB, MRI);
   }
+  case G_LSHR:
+    return selectShift(ARM_AM::ShiftOpc::lsr, MIB);
+  case G_ASHR:
+    return selectShift(ARM_AM::ShiftOpc::asr, MIB);
+  case G_SHL: {
+    return selectShift(ARM_AM::ShiftOpc::lsl, MIB);
+  }
   case G_GEP:
     I.setDesc(TII.get(ARM::ADDrr));
     MIB.add(predOps(ARMCC::AL)).add(condCodeOp());

test/CodeGen/ARM/GlobalISel/arm-instruction-select.mir

@@ -32,6 +32,10 @@
   define void @test_or_s32() { ret void }
   define void @test_xor_s32() { ret void }
 
+  define void @test_lshr_s32() { ret void }
+  define void @test_ashr_s32() { ret void }
+  define void @test_shl_s32() { ret void }
+
   define void @test_load_from_stack() { ret void }
   define void @test_load_f32() #0 { ret void }
   define void @test_load_f64() #0 { ret void }
@@ -891,6 +895,105 @@ body:             |
     ; CHECK: BX_RET 14, _, implicit %r0
 ...
 ---
+name:            test_lshr_s32
+# CHECK-LABEL: name: test_lshr_s32
+legalized:       true
+regBankSelected: true
+selected:        false
+# CHECK: selected: true
+registers:
+  - { id: 0, class: gprb }
+  - { id: 1, class: gprb }
+  - { id: 2, class: gprb }
+# CHECK: id: 0, class: gpr
+# CHECK: id: 1, class: gpr
+# CHECK: id: 2, class: gpr
+body:             |
+  bb.0:
+    liveins: %r0, %r1
+
+    %0(s32) = COPY %r0
+    ; CHECK: [[VREGX:%[0-9]+]] = COPY %r0
+
+    %1(s32) = COPY %r1
+    ; CHECK: [[VREGY:%[0-9]+]] = COPY %r1
+
+    %2(s32) = G_LSHR %0, %1
+    ; CHECK: [[VREGRES:%[0-9]+]] = MOVsr [[VREGX]], [[VREGY]], 3, 14, _, _
+
+    %r0 = COPY %2(s32)
+    ; CHECK: %r0 = COPY [[VREGRES]]
+
+    BX_RET 14, _, implicit %r0
+    ; CHECK: BX_RET 14, _, implicit %r0
+...
+---
+name:            test_ashr_s32
+# CHECK-LABEL: name: test_ashr_s32
+legalized:       true
+regBankSelected: true
+selected:        false
+# CHECK: selected: true
+registers:
+  - { id: 0, class: gprb }
+  - { id: 1, class: gprb }
+  - { id: 2, class: gprb }
+# CHECK: id: 0, class: gpr
+# CHECK: id: 1, class: gpr
+# CHECK: id: 2, class: gpr
+body:             |
+  bb.0:
+    liveins: %r0, %r1
+
+    %0(s32) = COPY %r0
+    ; CHECK: [[VREGX:%[0-9]+]] = COPY %r0
+
+    %1(s32) = COPY %r1
+    ; CHECK: [[VREGY:%[0-9]+]] = COPY %r1
+
+    %2(s32) = G_ASHR %0, %1
+    ; CHECK: [[VREGRES:%[0-9]+]] = MOVsr [[VREGX]], [[VREGY]], 1, 14, _, _
+
+    %r0 = COPY %2(s32)
+    ; CHECK: %r0 = COPY [[VREGRES]]
+
+    BX_RET 14, _, implicit %r0
+    ; CHECK: BX_RET 14, _, implicit %r0
+...
+---
+name:            test_shl_s32
+# CHECK-LABEL: name: test_shl_s32
+legalized:       true
+regBankSelected: true
+selected:        false
+# CHECK: selected: true
+registers:
+  - { id: 0, class: gprb }
+  - { id: 1, class: gprb }
+  - { id: 2, class: gprb }
+# CHECK: id: 0, class: gpr
+# CHECK: id: 1, class: gpr
+# CHECK: id: 2, class: gpr
+body:             |
+  bb.0:
+    liveins: %r0, %r1
+
+    %0(s32) = COPY %r0
+    ; CHECK: [[VREGX:%[0-9]+]] = COPY %r0
+
+    %1(s32) = COPY %r1
+    ; CHECK: [[VREGY:%[0-9]+]] = COPY %r1
+
+    %2(s32) = G_SHL %0, %1
+    ; CHECK: [[VREGRES:%[0-9]+]] = MOVsr [[VREGX]], [[VREGY]], 2, 14, _, _
+
+    %r0 = COPY %2(s32)
+    ; CHECK: %r0 = COPY [[VREGRES]]
+
+    BX_RET 14, _, implicit %r0
+    ; CHECK: BX_RET 14, _, implicit %r0
+...
+---
 name:            test_load_from_stack
 # CHECK-LABEL: name: test_load_from_stack
 legalized:       true