[AArch64][GlobalISel] Legalize G_FEXP2

[paquette]

Summary

Same as G_EXP. Add a test, and update legalizer-info-validation.mir and f16-instructions.ll.

[aemerson]

LGTM.

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

case TargetOpcode::G_FMUL:
     assert((Size == 32 || Size == 64) && "Unsupported size");
     return Size == 64 ? RTLIB::MUL_F64 : RTLIB::MUL_F32;
   case TargetOpcode::G_FDIV:
     assert((Size == 32 || Size == 64) && "Unsupported size");
     return Size == 64 ? RTLIB::DIV_F64 : RTLIB::DIV_F32;
   case TargetOpcode::G_FEXP:
     assert((Size == 32 || Size == 64) && "Unsupported size");
     return Size == 64 ? RTLIB::EXP_F64 : RTLIB::EXP_F32;
+  case TargetOpcode::G_FEXP2:
+    assert((Size == 32 || Size == 64) && "Unsupported size");
+    return Size == 64 ? RTLIB::EXP2_F64 : RTLIB::EXP2_F32;
   case TargetOpcode::G_FREM:
     return Size == 64 ? RTLIB::REM_F64 : RTLIB::REM_F32;
   case TargetOpcode::G_FPOW:
     return Size == 64 ? RTLIB::POW_F64 : RTLIB::POW_F32;
   case TargetOpcode::G_FMA:
     assert((Size == 32 || Size == 64) && "Unsupported size");
     return Size == 64 ? RTLIB::FMA_F64 : RTLIB::FMA_F32;
   case TargetOpcode::G_FSIN:
LegalizerHelper::libcall(MachineInstr &MI) {
   case TargetOpcode::G_FMA:
   case TargetOpcode::G_FPOW:
   case TargetOpcode::G_FREM:
   case TargetOpcode::G_FCOS:
   case TargetOpcode::G_FSIN:
   case TargetOpcode::G_FLOG10:
   case TargetOpcode::G_FLOG:
   case TargetOpcode::G_FLOG2:
-  case TargetOpcode::G_FEXP: {
+  case TargetOpcode::G_FEXP:
+  case TargetOpcode::G_FEXP2: {
     if (Size > 64) {
       LLVM_DEBUG(dbgs() << "Size " << Size << " too large to legalize.\n");
       return UnableToLegalize;
     }
     Type *HLTy = Size == 64 ? Type::getDoubleTy(Ctx) : Type::getFloatTy(Ctx);
     auto Status = simpleLibcall(MI, MIRBuilder, Size, HLTy);
     if (Status != Legalized)
       return Status;
LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
   case TargetOpcode::G_FFLOOR:
   case TargetOpcode::G_FCOS:
   case TargetOpcode::G_FSIN:
   case TargetOpcode::G_FLOG10:
   case TargetOpcode::G_FLOG:
   case TargetOpcode::G_FLOG2:
   case TargetOpcode::G_FSQRT:
   case TargetOpcode::G_FEXP:
+  case TargetOpcode::G_FEXP2:
     assert(TypeIdx == 0);
     Observer.changingInstr(MI);
 
     for (unsigned I = 1, E = MI.getNumOperands(); I != E; ++I)
       widenScalarSrc(MI, WideTy, I, TargetOpcode::G_FPEXT);
 
     widenScalarDst(MI, WideTy, 0, TargetOpcode::G_FPTRUNC);
     Observer.changedInstr(MI);

llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp

getActionDefinitionsBuilder({G_FCEIL, G_FABS, G_FSQRT, G_FFLOOR})
       .widenScalarIf(
           [=, &ST](const LegalityQuery &Query) {
             return Query.Types[0] == s16 && !ST.hasFullFP16();
           },
           [=](const LegalityQuery &Query) { return std::make_pair(0, s32); })
       .legalFor({s16, s32, s64, v2s32, v4s32, v2s64, v2s16, v4s16, v8s16});
 
   getActionDefinitionsBuilder(
-      {G_FCOS, G_FSIN, G_FLOG10, G_FLOG, G_FLOG2, G_FEXP})
+      {G_FCOS, G_FSIN, G_FLOG10, G_FLOG, G_FLOG2, G_FEXP, G_FEXP2})
       // We need a call for these, so we always need to scalarize.
       .scalarize(0)
       // Regardless of FP16 support, widen 16-bit elements to 32-bits.
       .minScalar(0, s32)
       .libcallFor({s32, s64, v2s32, v4s32, v2s64});
 
   getActionDefinitionsBuilder(G_INSERT)
       .unsupportedIf([=](const LegalityQuery &Query) {

llvm/test/CodeGen/AArch64/GlobalISel/legalize-fexp2.mir

+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -verify-machineinstrs -mtriple aarch64--- \
+# RUN: -run-pass=legalizer -mattr=+fullfp16 -global-isel %s -o - \
+# RUN: | FileCheck %s
+...
+---
+name:            test_v4f16.exp2
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $d0
+    ; CHECK-LABEL: name: test_v4f16.exp2
+    ; CHECK: liveins: $d0
+    ; CHECK: [[COPY:%[0-9]+]]:_(<4 x s16>) = COPY $d0
+    ; CHECK: [[UV:%[0-9]+]]:_(s16), [[UV1:%[0-9]+]]:_(s16), [[UV2:%[0-9]+]]:_(s16), [[UV3:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[COPY]](<4 x s16>)
+    ; CHECK: [[FPEXT:%[0-9]+]]:_(s32) = G_FPEXT [[UV]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY1]](s32)
+    ; CHECK: [[FPEXT1:%[0-9]+]]:_(s32) = G_FPEXT [[UV1]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT1]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC1:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY2]](s32)
+    ; CHECK: [[FPEXT2:%[0-9]+]]:_(s32) = G_FPEXT [[UV2]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT2]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC2:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY3]](s32)
+    ; CHECK: [[FPEXT3:%[0-9]+]]:_(s32) = G_FPEXT [[UV3]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT3]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC3:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY4]](s32)
+    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s16>) = G_BUILD_VECTOR [[FPTRUNC]](s16), [[FPTRUNC1]](s16), [[FPTRUNC2]](s16), [[FPTRUNC3]](s16)
+    ; CHECK: $d0 = COPY [[BUILD_VECTOR]](<4 x s16>)
+    ; CHECK: RET_ReallyLR implicit $d0
+    %0:_(<4 x s16>) = COPY $d0
+    %1:_(<4 x s16>) = G_FEXP2 %0
+    $d0 = COPY %1(<4 x s16>)
+    RET_ReallyLR implicit $d0
+
+...
+---
+name:            test_v8f16.exp2
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $q0
+    ; CHECK-LABEL: name: test_v8f16.exp2
+    ; CHECK: liveins: $q0
+    ; CHECK: [[COPY:%[0-9]+]]:_(<8 x s16>) = COPY $q0
+    ; CHECK: [[UV:%[0-9]+]]:_(s16), [[UV1:%[0-9]+]]:_(s16), [[UV2:%[0-9]+]]:_(s16), [[UV3:%[0-9]+]]:_(s16), [[UV4:%[0-9]+]]:_(s16), [[UV5:%[0-9]+]]:_(s16), [[UV6:%[0-9]+]]:_(s16), [[UV7:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[COPY]](<8 x s16>)
+    ; CHECK: [[FPEXT:%[0-9]+]]:_(s32) = G_FPEXT [[UV]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY1]](s32)
+    ; CHECK: [[FPEXT1:%[0-9]+]]:_(s32) = G_FPEXT [[UV1]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT1]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC1:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY2]](s32)
+    ; CHECK: [[FPEXT2:%[0-9]+]]:_(s32) = G_FPEXT [[UV2]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT2]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC2:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY3]](s32)
+    ; CHECK: [[FPEXT3:%[0-9]+]]:_(s32) = G_FPEXT [[UV3]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT3]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC3:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY4]](s32)
+    ; CHECK: [[FPEXT4:%[0-9]+]]:_(s32) = G_FPEXT [[UV4]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT4]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC4:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY5]](s32)
+    ; CHECK: [[FPEXT5:%[0-9]+]]:_(s32) = G_FPEXT [[UV5]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT5]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY6:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC5:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY6]](s32)
+    ; CHECK: [[FPEXT6:%[0-9]+]]:_(s32) = G_FPEXT [[UV6]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT6]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY7:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC6:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY7]](s32)
+    ; CHECK: [[FPEXT7:%[0-9]+]]:_(s32) = G_FPEXT [[UV7]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT7]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY8:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC7:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY8]](s32)
+    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<8 x s16>) = G_BUILD_VECTOR [[FPTRUNC]](s16), [[FPTRUNC1]](s16), [[FPTRUNC2]](s16), [[FPTRUNC3]](s16), [[FPTRUNC4]](s16), [[FPTRUNC5]](s16), [[FPTRUNC6]](s16), [[FPTRUNC7]](s16)
+    ; CHECK: $q0 = COPY [[BUILD_VECTOR]](<8 x s16>)
+    ; CHECK: RET_ReallyLR implicit $q0
+    %0:_(<8 x s16>) = COPY $q0
+    %1:_(<8 x s16>) = G_FEXP2 %0
+    $q0 = COPY %1(<8 x s16>)
+    RET_ReallyLR implicit $q0
+
+...
+---
+name:            test_v2f32.exp2
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $d0
+    ; CHECK-LABEL: name: test_v2f32.exp2
+    ; CHECK: liveins: $d0
+    ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s32>) = COPY $d0
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<2 x s32>)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[UV]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[UV1]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[COPY1]](s32), [[COPY2]](s32)
+    ; CHECK: $d0 = COPY [[BUILD_VECTOR]](<2 x s32>)
+    ; CHECK: RET_ReallyLR implicit $d0
+    %0:_(<2 x s32>) = COPY $d0
+    %1:_(<2 x s32>) = G_FEXP2 %0
+    $d0 = COPY %1(<2 x s32>)
+    RET_ReallyLR implicit $d0
+
+...
+---
+name:            test_v4f32.exp2
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $q0
+    ; CHECK-LABEL: name: test_v4f32.exp2
+    ; CHECK: liveins: $q0
+    ; CHECK: [[COPY:%[0-9]+]]:_(<4 x s32>) = COPY $q0
+    ; CHECK: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32), [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY]](<4 x s32>)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[UV]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[UV1]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[UV2]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[UV3]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s32>) = G_BUILD_VECTOR [[COPY1]](s32), [[COPY2]](s32), [[COPY3]](s32), [[COPY4]](s32)
+    ; CHECK: $q0 = COPY [[BUILD_VECTOR]](<4 x s32>)
+    ; CHECK: RET_ReallyLR implicit $q0
+    %0:_(<4 x s32>) = COPY $q0
+    %1:_(<4 x s32>) = G_FEXP2 %0
+    $q0 = COPY %1(<4 x s32>)
+    RET_ReallyLR implicit $q0
+
+...
+---
+name:            test_v2f64.exp2
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $q0
+    ; CHECK-LABEL: name: test_v2f64.exp2
+    ; CHECK: liveins: $q0
+    ; CHECK: [[COPY:%[0-9]+]]:_(<2 x s64>) = COPY $q0
+    ; CHECK: [[UV:%[0-9]+]]:_(s64), [[UV1:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[COPY]](<2 x s64>)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $d0 = COPY [[UV]](s64)
+    ; CHECK: BL &exp2, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $d0, implicit-def $d0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $d0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $d0 = COPY [[UV1]](s64)
+    ; CHECK: BL &exp2, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $d0, implicit-def $d0
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s64) = COPY $d0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<2 x s64>) = G_BUILD_VECTOR [[COPY1]](s64), [[COPY2]](s64)
+    ; CHECK: $q0 = COPY [[BUILD_VECTOR]](<2 x s64>)
+    ; CHECK: RET_ReallyLR implicit $q0
+    %0:_(<2 x s64>) = COPY $q0
+    %1:_(<2 x s64>) = G_FEXP2 %0
+    $q0 = COPY %1(<2 x s64>)
+    RET_ReallyLR implicit $q0
+
+...
+---
+name:            test_exp2_half
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $h0
+    ; CHECK-LABEL: name: test_exp2_half
+    ; CHECK: liveins: $h0
+    ; CHECK: [[COPY:%[0-9]+]]:_(s16) = COPY $h0
+    ; CHECK: [[FPEXT:%[0-9]+]]:_(s32) = G_FPEXT [[COPY]](s16)
+    ; CHECK: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: $s0 = COPY [[FPEXT]](s32)
+    ; CHECK: BL &exp2f, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $s0, implicit-def $s0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $s0
+    ; CHECK: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK: [[FPTRUNC:%[0-9]+]]:_(s16) = G_FPTRUNC [[COPY1]](s32)
+    ; CHECK: $h0 = COPY [[FPTRUNC]](s16)
+    ; CHECK: RET_ReallyLR implicit $h0
+    %0:_(s16) = COPY $h0
+    %1:_(s16) = G_FEXP2 %0
+    $h0 = COPY %1(s16)
+    RET_ReallyLR implicit $h0

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

 #
 # DEBUG-NEXT: G_FPOW (opcode {{[0-9]+}}): 1 type index
 # DEBUG:      .. the first uncovered type index: 1, OK
 #
 # DEBUG-NEXT: G_FEXP (opcode {{[0-9]+}}): 1 type index
 # DEBUG:      .. the first uncovered type index: 1, OK
 #
 # DEBUG-NEXT: G_FEXP2 (opcode {{[0-9]+}}): 1 type index
-# DEBUG:      .. type index coverage check SKIPPED: no rules defined
+# DEBUG:      .. the first uncovered type index: 1, OK
 #
 # DEBUG-NEXT: G_FLOG (opcode {{[0-9]+}}): 1 type index
 # DEBUG:      .. the first uncovered type index: 1, OK
 #
 # DEBUG-NEXT: G_FLOG2 (opcode {{[0-9]+}}): 1 type index
 # DEBUG:      .. the first uncovered type index: 1, OK
 #
 # DEBUG-NEXT: G_FLOG10 (opcode {{[0-9]+}}): 1 type index

llvm/test/CodeGen/AArch64/f16-instructions.ll

 ; CHECK-COMMON-LABEL: test_exp2:
 ; CHECK-COMMON-NEXT: stp x29, x30, [sp, #-16]!
 ; CHECK-COMMON-NEXT: mov  x29, sp
 ; CHECK-COMMON-NEXT: fcvt s0, h0
 ; CHECK-COMMON-NEXT: bl {{_?}}exp2f
 ; CHECK-COMMON-NEXT: fcvt h0, s0
 ; CHECK-COMMON-NEXT: ldp x29, x30, [sp], #16
 ; CHECK-COMMON-NEXT: ret
+
+; GISEL-LABEL: test_exp2:
+; GISEL-NEXT: stp x29, x30, [sp, #-16]!
+; GISEL-NEXT: mov  x29, sp
+; GISEL-NEXT: fcvt s0, h0
+; GISEL-NEXT: bl {{_?}}exp2f
+; GISEL-NEXT: fcvt h0, s0
+; GISEL-NEXT: ldp x29, x30, [sp], #16
+; GISEL-NEXT: ret
 define half @test_exp2(half %a) #0 {
   %r = call half @llvm.exp2.f16(half %a)
   ret half %r
 }
 
 ; FALLBACK-NOT: remark:{{.*}}test_log
 ; FALLBACK-FP16-NOT: remark:{{.*}}test_log