[GlobalISel] Accept multiple vregs for lowerCall's result

Change the interface of CallLowering::lowerCall to accept several
virtual registers for the call result, instead of just one.  This is a
follow-up to D46018.

CallLowering::lowerReturn was similarly refactored in D49660 and
lowerFormalArguments in D63549.

With this change, we no longer pack the virtual registers generated for
aggregates into one big lump before delegating to the target. Therefore,
the target can decide itself whether it wants to handle them as separate
pieces or use one big register.

ARM and AArch64 have been updated to use the passed in virtual registers
directly, which means we no longer need to generate so many
merge/extract instructions.

NFCI for AMDGPU, Mips and X86.

Differential Revision: https://reviews.llvm.org/D63550

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364511 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/GlobalISel/CallLowering.h b/include/llvm/CodeGen/GlobalISel/CallLowering.h
index b0a7444..99c6b4c 100644 (file)
--- a/include/llvm/CodeGen/GlobalISel/CallLowering.h
+++ b/include/llvm/CodeGen/GlobalISel/CallLowering.h
@@ -258,8 +258,9 @@ public:
   ///
   /// \p CI is the call/invoke instruction.
   ///
-  /// \p ResReg is a register where the call's return value should be stored (or
-  /// 0 if there is no return value).
+  /// \p ResRegs are the registers where the call's return value should be
+  /// stored (or 0 if there is no return value). There will be one register for
+  /// each non-aggregate type, as returned by \c computeValueLLTs.
   ///
   /// \p ArgRegs is a list of virtual registers containing each argument that
   /// needs to be passed.
@@ -275,10 +276,9 @@ public:
   ///
   /// \return true if the lowering succeeded, false otherwise.
   bool lowerCall(MachineIRBuilder &MIRBuilder, ImmutableCallSite CS,
-                 Register ResReg, ArrayRef<Register> ArgRegs,
+                 ArrayRef<Register> ResRegs, ArrayRef<Register> ArgRegs,
                  Register SwiftErrorVReg,
                  std::function<unsigned()> GetCalleeReg) const;
-
 };
 
 } // end namespace llvm

diff --git a/lib/CodeGen/GlobalISel/CallLowering.cpp b/lib/CodeGen/GlobalISel/CallLowering.cpp
index b2838d8..0772021 100644 (file)
--- a/lib/CodeGen/GlobalISel/CallLowering.cpp
+++ b/lib/CodeGen/GlobalISel/CallLowering.cpp
@@ -28,7 +28,8 @@ using namespace llvm;
 void CallLowering::anchor() {}
 
 bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, ImmutableCallSite CS,
-                             Register ResReg, ArrayRef<Register> ArgRegs,
+                             ArrayRef<Register> ResRegs,
+                             ArrayRef<Register> ArgRegs,
                              Register SwiftErrorVReg,
                              std::function<unsigned()> GetCalleeReg) const {
   auto &DL = CS.getParent()->getParent()->getParent()->getDataLayout();
@@ -56,7 +57,7 @@ bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, ImmutableCallSite CS,
   else
     Callee = MachineOperand::CreateReg(GetCalleeReg(), false);
 
-  ArgInfo OrigRet{ResReg, CS.getType(), ISD::ArgFlagsTy{}};
+  ArgInfo OrigRet{ResRegs, CS.getType(), ISD::ArgFlagsTy{}};
   if (!OrigRet.Ty->isVoidTy())
     setArgFlags(OrigRet, AttributeList::ReturnIndex, DL, CS);
 

diff --git a/lib/CodeGen/GlobalISel/IRTranslator.cpp b/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 5e5e1be..2f07659 100644 (file)
--- a/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -1585,10 +1585,7 @@ bool IRTranslator::translateCall(const User &U, MachineIRBuilder &MIRBuilder) {
   }
 
   if (!F || !F->isIntrinsic() || ID == Intrinsic::not_intrinsic) {
-    bool IsSplitType = valueIsSplit(CI);
-    Register Res = IsSplitType ? MRI->createGenericVirtualRegister(
-                                     getLLTForType(*CI.getType(), *DL))
-                               : getOrCreateVReg(CI);
+    ArrayRef<Register> Res = getOrCreateVRegs(CI);
 
     SmallVector<Register, 8> Args;
     Register SwiftErrorVReg;
@@ -1611,9 +1608,6 @@ bool IRTranslator::translateCall(const User &U, MachineIRBuilder &MIRBuilder) {
         CLI->lowerCall(MIRBuilder, &CI, Res, Args, SwiftErrorVReg,
                        [&]() { return getOrCreateVReg(*CI.getCalledValue()); });
 
-    if (IsSplitType)
-      unpackRegs(CI, Res, MIRBuilder);
-
     return Success;
   }
 
@@ -1687,11 +1681,11 @@ bool IRTranslator::translateInvoke(const User &U,
   MCSymbol *BeginSymbol = Context.createTempSymbol();
   MIRBuilder.buildInstr(TargetOpcode::EH_LABEL).addSym(BeginSymbol);
 
-  Register Res;
+  ArrayRef<Register> Res;
   if (!I.getType()->isVoidTy())
-    Res = MRI->createGenericVirtualRegister(getLLTForType(*I.getType(), *DL));
+    Res = getOrCreateVRegs(I);
   SmallVector<Register, 8> Args;
-  Register SwiftErrorVReg;
+  Register SwiftErrorVReg = 0;
   for (auto &Arg : I.arg_operands()) {
     if (CLI->supportSwiftError() && isSwiftError(Arg)) {
       LLT Ty = getLLTForType(*Arg->getType(), *DL);
@@ -1711,8 +1705,6 @@ bool IRTranslator::translateInvoke(const User &U,
                       [&]() { return getOrCreateVReg(*I.getCalledValue()); }))
     return false;
 
-  unpackRegs(I, Res, MIRBuilder);
-
   MCSymbol *EndSymbol = Context.createTempSymbol();
   MIRBuilder.buildInstr(TargetOpcode::EH_LABEL).addSym(EndSymbol);
 

diff --git a/lib/Target/AArch64/AArch64CallLowering.cpp b/lib/Target/AArch64/AArch64CallLowering.cpp
index effca68..1fa12b0 100644 (file)
--- a/lib/Target/AArch64/AArch64CallLowering.cpp
+++ b/lib/Target/AArch64/AArch64CallLowering.cpp
@@ -498,24 +498,18 @@ bool AArch64CallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
   // symmetry with the arugments, the physical register must be an
   // implicit-define of the call instruction.
   CCAssignFn *RetAssignFn = TLI.CCAssignFnForReturn(F.getCallingConv());
-  assert(OrigRet.Regs.size() == 1 && "Can't handle multple regs yet");
-  if (OrigRet.Regs[0]) {
+  if (!OrigRet.Ty->isVoidTy()) {
     SplitArgs.clear();
 
-    SmallVector<uint64_t, 8> RegOffsets;
-    SmallVector<Register, 8> SplitRegs;
     splitToValueTypes(OrigRet, SplitArgs, DL, MRI, F.getCallingConv(),
                       [&](unsigned Reg, uint64_t Offset) {
-                        RegOffsets.push_back(Offset);
-                        SplitRegs.push_back(Reg);
+                        llvm_unreachable(
+                            "Call results should already be split");
                       });
 
     CallReturnHandler Handler(MIRBuilder, MRI, MIB, RetAssignFn);
     if (!handleAssignments(MIRBuilder, SplitArgs, Handler))
       return false;
-
-    if (!RegOffsets.empty())
-      MIRBuilder.buildSequence(OrigRet.Regs[0], SplitRegs, RegOffsets);
   }
 
   if (SwiftErrorVReg) {

diff --git a/lib/Target/ARM/ARMCallLowering.cpp b/lib/Target/ARM/ARMCallLowering.cpp
index ea5bfb5..71b9251 100644 (file)
--- a/lib/Target/ARM/ARMCallLowering.cpp
+++ b/lib/Target/ARM/ARMCallLowering.cpp
@@ -619,21 +619,14 @@ bool ARMCallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
       return false;
 
     ArgInfos.clear();
-    SmallVector<Register, 8> SplitRegs;
-    splitToValueTypes(OrigRet, ArgInfos, MF,
-                      [&](Register Reg) { SplitRegs.push_back(Reg); });
+    splitToValueTypes(OrigRet, ArgInfos, MF, [&](Register Reg) {
+      llvm_unreachable("Call results should already be split");
+    });
 
     auto RetAssignFn = TLI.CCAssignFnForReturn(CallConv, IsVarArg);
     CallReturnHandler RetHandler(MIRBuilder, MRI, MIB, RetAssignFn);
     if (!handleAssignments(MIRBuilder, ArgInfos, RetHandler))
       return false;
-
-    if (!SplitRegs.empty()) {
-      // We have split the value and allocated each individual piece, now build
-      // it up again.
-      assert(OrigRet.Regs.size() == 1 && "Can't handle multple regs yet");
-      MIRBuilder.buildMerge(OrigRet.Regs[0], SplitRegs);
-    }
   }
 
   // We now know the size of the stack - update the ADJCALLSTACKDOWN

diff --git a/lib/Target/ARM/ARMLegalizerInfo.cpp b/lib/Target/ARM/ARMLegalizerInfo.cpp
index 796eaee..73a57b2 100644 (file)
--- a/lib/Target/ARM/ARMLegalizerInfo.cpp
+++ b/lib/Target/ARM/ARMLegalizerInfo.cpp
@@ -369,7 +369,7 @@ bool ARMLegalizerInfo::legalizeCustom(MachineInstr &MI,
     return false;
   case G_SREM:
   case G_UREM: {
-    unsigned OriginalResult = MI.getOperand(0).getReg();
+    Register OriginalResult = MI.getOperand(0).getReg();
     auto Size = MRI.getType(OriginalResult).getSizeInBits();
     if (Size != 32)
       return false;
@@ -378,24 +378,17 @@ bool ARMLegalizerInfo::legalizeCustom(MachineInstr &MI,
         MI.getOpcode() == G_SREM ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
 
     // Our divmod libcalls return a struct containing the quotient and the
-    // remainder. We need to create a virtual register for it.
+    // remainder. Create a new, unused register for the quotient and use the
+    // destination of the original instruction for the remainder.
     Type *ArgTy = Type::getInt32Ty(Ctx);
     StructType *RetTy = StructType::get(Ctx, {ArgTy, ArgTy}, /* Packed */ true);
-    auto RetVal = MRI.createGenericVirtualRegister(
-        getLLTForType(*RetTy, MIRBuilder.getMF().getDataLayout()));
-
-    auto Status = createLibcall(MIRBuilder, Libcall, {RetVal, RetTy},
+    Register RetRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
+                          OriginalResult};
+    auto Status = createLibcall(MIRBuilder, Libcall, {RetRegs, RetTy},
                                 {{MI.getOperand(1).getReg(), ArgTy},
                                  {MI.getOperand(2).getReg(), ArgTy}});
     if (Status != LegalizerHelper::Legalized)
       return false;
-
-    // The remainder is the second result of divmod. Split the return value into
-    // a new, unused register for the quotient and the destination of the
-    // original instruction for the remainder.
-    MIRBuilder.buildUnmerge(
-        {MRI.createGenericVirtualRegister(LLT::scalar(32)), OriginalResult},
-        RetVal);
     break;
   }
   case G_FCMP: {

diff --git a/lib/Target/Mips/MipsCallLowering.cpp b/lib/Target/Mips/MipsCallLowering.cpp
index 8911ae3..8d14ecc 100644 (file)
--- a/lib/Target/Mips/MipsCallLowering.cpp
+++ b/lib/Target/Mips/MipsCallLowering.cpp
@@ -514,7 +514,6 @@ bool MipsCallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
       return false;
   }
 
-  assert(OrigRet.Regs.size() == 1 && "Can't handle multple regs yet");
   if (OrigRet.Regs[0] && !isSupportedType(OrigRet.Ty))
     return false;
 

diff --git a/lib/Target/X86/X86CallLowering.cpp b/lib/Target/X86/X86CallLowering.cpp
index e41bcfa..3a980f4 100644 (file)
--- a/lib/Target/X86/X86CallLowering.cpp
+++ b/lib/Target/X86/X86CallLowering.cpp
@@ -453,7 +453,8 @@ bool X86CallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
   // implicit-define of the call instruction.
 
   if (!OrigRet.Ty->isVoidTy()) {
-    assert(OrigRet.Regs.size() == 1 && "Can't handle multple regs yet");
+    if (OrigRet.Regs.size() > 1)
+      return false;
 
     SplitArgs.clear();
     SmallVector<Register, 8> NewRegs;

diff --git a/test/CodeGen/AArch64/GlobalISel/call-translator.ll b/test/CodeGen/AArch64/GlobalISel/call-translator.ll
index 6ab4fea..cda1dc3 100644 (file)
--- a/test/CodeGen/AArch64/GlobalISel/call-translator.ll
+++ b/test/CodeGen/AArch64/GlobalISel/call-translator.ll
@@ -131,8 +131,7 @@ define {double, i64, i32} @test_struct_return({double, i64, i32}* %addr) {
 ; CHECK: [[E1:%[0-9]+]]:_(s64) = COPY $x1
 ; CHECK: [[E2:%[0-9]+]]:_(s64) = COPY $x2
 ; CHECK: [[E3:%[0-9]+]]:_(s64) = COPY $x3
-; CHECK: [[RES:%[0-9]+]]:_(s256) = G_MERGE_VALUES [[E0]](s64), [[E1]](s64), [[E2]](s64), [[E3]](s64)
-; CHECK: G_EXTRACT [[RES]](s256), 64
+; CHECK: $x0 = COPY [[E1]]
 declare [4 x i64] @arr_callee([4 x i64])
 define i64 @test_arr_call([4 x i64]* %addr) {
   %arg = load [4 x i64], [4 x i64]* %addr

diff --git a/test/CodeGen/ARM/GlobalISel/arm-param-lowering.ll b/test/CodeGen/ARM/GlobalISel/arm-param-lowering.ll
index f5c2cb4..422785a 100644 (file)
--- a/test/CodeGen/ARM/GlobalISel/arm-param-lowering.ll
+++ b/test/CodeGen/ARM/GlobalISel/arm-param-lowering.ll
@@ -214,17 +214,13 @@ define arm_aapcscc [3 x i32] @test_tiny_int_arrays([2 x i32] %arr) {
 ; CHECK: [[R0:%[0-9]+]]:_(s32) = COPY $r0
 ; CHECK: [[R1:%[0-9]+]]:_(s32) = COPY $r1
 ; CHECK: [[R2:%[0-9]+]]:_(s32) = COPY $r2
-; CHECK: [[RES_ARR:%[0-9]+]]:_(s96) = G_MERGE_VALUES [[R0]](s32), [[R1]](s32), [[R2]](s32)
 ; CHECK: ADJCALLSTACKUP 0, 0, 14, $noreg, implicit-def $sp, implicit $sp
-; CHECK: [[EXT3:%[0-9]+]]:_(s32) = G_EXTRACT [[RES_ARR]](s96), 0
-; CHECK: [[EXT4:%[0-9]+]]:_(s32) = G_EXTRACT [[RES_ARR]](s96), 32
-; CHECK: [[EXT5:%[0-9]+]]:_(s32) = G_EXTRACT [[RES_ARR]](s96), 64
 ; FIXME: This doesn't seem correct with regard to the AAPCS docs (which say
 ; that composite types larger than 4 bytes should be passed through memory),
 ; but it's what DAGISel does. We should fix it in the common code for both.
-; CHECK: $r0 = COPY [[EXT3]]
-; CHECK: $r1 = COPY [[EXT4]]
-; CHECK: $r2 = COPY [[EXT5]]
+; CHECK: $r0 = COPY [[R0]]
+; CHECK: $r1 = COPY [[R1]]
+; CHECK: $r2 = COPY [[R2]]
 ; ARM: BX_RET 14, $noreg, implicit $r0, implicit $r1, implicit $r2
 ; THUMB: tBX_RET 14, $noreg, implicit $r0, implicit $r1, implicit $r2
 entry:
@@ -352,12 +348,9 @@ define arm_aapcscc [2 x float] @test_fp_arrays_aapcs([3 x double] %arr) {
 ; THUMB: tBL 14, $noreg, @fp_arrays_aapcs_target, csr_aapcs, implicit-def $lr, implicit $sp, implicit $r0, implicit $r1, implicit $r2, implicit $r3, implicit-def $r0, implicit-def $r1
 ; CHECK: [[R0:%[0-9]+]]:_(s32) = COPY $r0
 ; CHECK: [[R1:%[0-9]+]]:_(s32) = COPY $r1
-; CHECK: [[R_MERGED:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[R0]](s32), [[R1]](s32)
 ; CHECK: ADJCALLSTACKUP 8, 0, 14, $noreg, implicit-def $sp, implicit $sp
-; CHECK: [[EXT4:%[0-9]+]]:_(s32) = G_EXTRACT [[R_MERGED]](s64), 0
-; CHECK: [[EXT5:%[0-9]+]]:_(s32) = G_EXTRACT [[R_MERGED]](s64), 32
-; CHECK: $r0 = COPY [[EXT4]]
-; CHECK: $r1 = COPY [[EXT5]]
+; CHECK: $r0 = COPY [[R0]]
+; CHECK: $r1 = COPY [[R1]]
 ; ARM: BX_RET 14, $noreg, implicit $r0, implicit $r1
 ; THUMB: tBX_RET 14, $noreg, implicit $r0, implicit $r1
 entry:
@@ -434,16 +427,11 @@ define arm_aapcs_vfpcc [4 x float] @test_fp_arrays_aapcs_vfp([3 x double] %x, [3
 ; CHECK: [[R1:%[0-9]+]]:_(s32) = COPY $s1
 ; CHECK: [[R2:%[0-9]+]]:_(s32) = COPY $s2
 ; CHECK: [[R3:%[0-9]+]]:_(s32) = COPY $s3
-; CHECK: [[R_MERGED:%[0-9]+]]:_(s128) = G_MERGE_VALUES [[R0]](s32), [[R1]](s32), [[R2]](s32), [[R3]](s32)
 ; CHECK: ADJCALLSTACKUP 32, 0, 14, $noreg, implicit-def $sp, implicit $sp
-; CHECK: [[EXT11:%[0-9]+]]:_(s32) = G_EXTRACT [[R_MERGED]](s128), 0
-; CHECK: [[EXT12:%[0-9]+]]:_(s32) = G_EXTRACT [[R_MERGED]](s128), 32
-; CHECK: [[EXT13:%[0-9]+]]:_(s32) = G_EXTRACT [[R_MERGED]](s128), 64
-; CHECK: [[EXT14:%[0-9]+]]:_(s32) = G_EXTRACT [[R_MERGED]](s128), 96
-; CHECK: $s0 = COPY [[EXT11]]
-; CHECK: $s1 = COPY [[EXT12]]
-; CHECK: $s2 = COPY [[EXT13]]
-; CHECK: $s3 = COPY [[EXT14]]
+; CHECK: $s0 = COPY [[R0]]
+; CHECK: $s1 = COPY [[R1]]
+; CHECK: $s2 = COPY [[R2]]
+; CHECK: $s3 = COPY [[R3]]
 ; ARM: BX_RET 14, $noreg, implicit $s0, implicit $s1, implicit $s2, implicit $s3
 ; THUMB: tBX_RET 14, $noreg, implicit $s0, implicit $s1, implicit $s2, implicit $s3
 entry:
@@ -488,14 +476,11 @@ define arm_aapcscc [2 x i32*] @test_tough_arrays([6 x [4 x i32]] %arr) {
 ; CHECK: G_STORE [[LAST_STACK_ELEMENT]](s32), [[LAST_STACK_ARG_ADDR]]{{.*}}store 4
 ; ARM: BL @tough_arrays_target, csr_aapcs, implicit-def $lr, implicit $sp, implicit $r0, implicit $r1, implicit $r2, implicit $r3, implicit-def $r0, implicit-def $r1
 ; THUMB: tBL 14, $noreg, @tough_arrays_target, csr_aapcs, implicit-def $lr, implicit $sp, implicit $r0, implicit $r1, implicit $r2, implicit $r3, implicit-def $r0, implicit-def $r1
-; CHECK: [[R0:%[0-9]+]]:_(s32) = COPY $r0
-; CHECK: [[R1:%[0-9]+]]:_(s32) = COPY $r1
-; CHECK: [[RES_ARR:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[R0]](s32), [[R1]](s32)
+; CHECK: [[R0:%[0-9]+]]:_(p0) = COPY $r0
+; CHECK: [[R1:%[0-9]+]]:_(p0) = COPY $r1
 ; CHECK: ADJCALLSTACKUP 80, 0, 14, $noreg, implicit-def $sp, implicit $sp
-; CHECK: [[EXT1:%[0-9]+]]:_(p0) = G_EXTRACT [[RES_ARR]](s64), 0
-; CHECK: [[EXT2:%[0-9]+]]:_(p0) = G_EXTRACT [[RES_ARR]](s64), 32
-; CHECK: $r0 = COPY [[EXT1]]
-; CHECK: $r1 = COPY [[EXT2]]
+; CHECK: $r0 = COPY [[R0]]
+; CHECK: $r1 = COPY [[R1]]
 ; ARM: BX_RET 14, $noreg, implicit $r0, implicit $r1
 ; THUMB: tBX_RET 14, $noreg, implicit $r0, implicit $r1
 entry:
@@ -521,12 +506,9 @@ define arm_aapcscc {i32, i32} @test_structs({i32, i32} %x) {
 ; THUMB: tBL 14, $noreg, @structs_target, csr_aapcs, implicit-def $lr, implicit $sp, implicit $r0, implicit $r1, implicit-def $r0, implicit-def $r1
 ; CHECK: [[R0:%[0-9]+]]:_(s32) = COPY $r0
 ; CHECK: [[R1:%[0-9]+]]:_(s32) = COPY $r1
-; CHECK: [[R:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[R0]](s32), [[R1]](s32)
 ; CHECK: ADJCALLSTACKUP 0, 0, 14, $noreg, implicit-def $sp, implicit $sp
-; CHECK: [[EXT3:%[0-9]+]]:_(s32) = G_EXTRACT [[R]](s64), 0
-; CHECK: [[EXT4:%[0-9]+]]:_(s32) = G_EXTRACT [[R]](s64), 32
-; CHECK: $r0 = COPY [[EXT3]](s32)
-; CHECK: $r1 = COPY [[EXT4]](s32)
+; CHECK: $r0 = COPY [[R0]](s32)
+; CHECK: $r1 = COPY [[R1]](s32)
 ; ARM: BX_RET 14, $noreg, implicit $r0, implicit $r1
 ; THUMB: tBX_RET 14, $noreg, implicit $r0, implicit $r1
   %r = notail call arm_aapcscc {i32, i32} @structs_target({i32, i32} %x)