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ARM: treat [N x i32] and [N x i64] as AAPCS composite types

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The logic is almost there already, with our special homogeneous aggregate
handling. Tweaking it like this allows front-ends to emit AAPCS compliant code
without ever having to count registers or add discarded padding arguments.

Only arrays of i32 and i64 are needed to model AAPCS rules, but I decided to
apply the logic to all integer arrays for more consistency.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230348 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tim Northover
2015-02-24 17:22:34 +00:00
parent bc8f84c030
commit 5530ac99e6
6 changed files with 214 additions and 74 deletions
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5
include/llvm/CodeGen/CallingConvLower.h
View File

@@ -122,8 +122,8 @@ public:
// There is no need to differentiate between a pending CCValAssign and other
// kinds, as they are stored in a different list.
static CCValAssign getPending(unsigned ValNo, MVT ValVT, MVT LocVT,
LocInfo HTP) {
return getReg(ValNo, ValVT, 0, LocVT, HTP);
LocInfo HTP, unsigned ExtraInfo = 0) {
return getReg(ValNo, ValVT, ExtraInfo, LocVT, HTP);
}
void convertToReg(unsigned RegNo) {
@@ -146,6 +146,7 @@ public:
unsigned getLocReg() const { assert(isRegLoc()); return Loc; }
unsigned getLocMemOffset() const { assert(isMemLoc()); return Loc; }
unsigned getExtraInfo() const { return Loc; }
MVT getLocVT() const { return LocVT; }
LocInfo getLocInfo() const { return HTP; }

15
lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
View File

@@ -7463,11 +7463,8 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
}
if (Args[i].isNest)
Flags.setNest();
if (NeedsRegBlock) {
if (NeedsRegBlock)
Flags.setInConsecutiveRegs();
if (Value == NumValues - 1)
Flags.setInConsecutiveRegsLast();
}
Flags.setOrigAlign(OriginalAlignment);
MVT PartVT = getRegisterType(CLI.RetTy->getContext(), VT);
@@ -7516,6 +7513,9 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
CLI.Outs.push_back(MyFlags);
CLI.OutVals.push_back(Parts[j]);
}
if (NeedsRegBlock && Value == NumValues - 1)
CLI.Outs[CLI.Outs.size() - 1].Flags.setInConsecutiveRegsLast();
}
}
@@ -7731,11 +7731,8 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
}
if (F.getAttributes().hasAttribute(Idx, Attribute::Nest))
Flags.setNest();
if (NeedsRegBlock) {
if (NeedsRegBlock)
Flags.setInConsecutiveRegs();
if (Value == NumValues - 1)
Flags.setInConsecutiveRegsLast();
}
Flags.setOrigAlign(OriginalAlignment);
MVT RegisterVT = TLI->getRegisterType(*CurDAG->getContext(), VT);
@@ -7750,6 +7747,8 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
MyFlags.Flags.setOrigAlign(1);
Ins.push_back(MyFlags);
}
if (NeedsRegBlock && Value == NumValues - 1)
Ins[Ins.size() - 1].Flags.setInConsecutiveRegsLast();
PartBase += VT.getStoreSize();
}
}

95
lib/Target/ARM/ARMCallingConv.h
View File

@@ -160,6 +160,8 @@ static bool RetCC_ARM_AAPCS_Custom_f64(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
State);
}
static const uint16_t RRegList[] = { ARM::R0, ARM::R1, ARM::R2, ARM::R3 };
static const uint16_t SRegList[] = { ARM::S0, ARM::S1, ARM::S2, ARM::S3,
ARM::S4, ARM::S5, ARM::S6, ARM::S7,
ARM::S8, ARM::S9, ARM::S10, ARM::S11,
@@ -168,34 +170,51 @@ static const uint16_t DRegList[] = { ARM::D0, ARM::D1, ARM::D2, ARM::D3,
ARM::D4, ARM::D5, ARM::D6, ARM::D7 };
static const uint16_t QRegList[] = { ARM::Q0, ARM::Q1, ARM::Q2, ARM::Q3 };
// Allocate part of an AAPCS HFA or HVA. We assume that each member of the HA
// has InConsecutiveRegs set, and that the last member also has
// InConsecutiveRegsLast set. We must process all members of the HA before
// we can allocate it, as we need to know the total number of registers that
// will be needed in order to (attempt to) allocate a contiguous block.
static bool CC_ARM_AAPCS_Custom_HA(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
static bool CC_ARM_AAPCS_Custom_Aggregate(unsigned &ValNo, MVT &ValVT,
MVT &LocVT,
CCValAssign::LocInfo &LocInfo,
ISD::ArgFlagsTy &ArgFlags, CCState &State) {
SmallVectorImpl<CCValAssign> &PendingHAMembers = State.getPendingLocs();
ISD::ArgFlagsTy &ArgFlags,
CCState &State) {
SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
// AAPCS HFAs must have 1-4 elements, all of the same type
assert(PendingHAMembers.size() < 4);
if (PendingHAMembers.size() > 0)
assert(PendingHAMembers[0].getLocVT() == LocVT);
if (PendingMembers.size() > 0)
assert(PendingMembers[0].getLocVT() == LocVT);
// Add the argument to the list to be allocated once we know the size of the
// HA
PendingHAMembers.push_back(
CCValAssign::getPending(ValNo, ValVT, LocVT, LocInfo));
// aggregate. Store the type's required alignmnent as extra info for later: in
// the [N x i64] case all trace has been removed by the time we actually get
// to do allocation.
PendingMembers.push_back(CCValAssign::getPending(ValNo, ValVT, LocVT, LocInfo,
ArgFlags.getOrigAlign()));
if (ArgFlags.isInConsecutiveRegsLast()) {
assert(PendingHAMembers.size() > 0 && PendingHAMembers.size() <= 4 &&
"Homogeneous aggregates must have between 1 and 4 members");
if (!ArgFlags.isInConsecutiveRegsLast())
return true;
// Try to allocate a contiguous block of registers, each of the correct
// size to hold one member.
unsigned Align = std::min(PendingMembers[0].getExtraInfo(), 8U);
ArrayRef<uint16_t> RegList;
switch (LocVT.SimpleTy) {
case MVT::i32: {
RegList = RRegList;
unsigned RegIdx = State.getFirstUnallocated(RegList);
// First consume all registers that would give an unaligned object. Whether
// we go on stack or in regs, no-one will be using them in future.
unsigned RegAlign = RoundUpToAlignment(Align, 4) / 4;
while (RegIdx % RegAlign != 0 && RegIdx < RegList.size())
State.AllocateReg(RegList[RegIdx++]);
break;
}
case MVT::f32:
RegList = SRegList;
break;
@@ -206,43 +225,59 @@ static bool CC_ARM_AAPCS_Custom_HA(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
RegList = QRegList;
break;
default:
llvm_unreachable("Unexpected member type for HA");
llvm_unreachable("Unexpected member type for block aggregate");
break;
}
unsigned RegResult =
State.AllocateRegBlock(RegList, PendingHAMembers.size());
unsigned RegResult = State.AllocateRegBlock(RegList, PendingMembers.size());
if (RegResult) {
for (SmallVectorImpl<CCValAssign>::iterator It = PendingHAMembers.begin();
It != PendingHAMembers.end(); ++It) {
for (SmallVectorImpl<CCValAssign>::iterator It = PendingMembers.begin();
It != PendingMembers.end(); ++It) {
It->convertToReg(RegResult);
State.addLoc(*It);
++RegResult;
}
PendingHAMembers.clear();
PendingMembers.clear();
return true;
}
// Register allocation failed, fall back to the stack
// Mark all VFP regs as unavailable (AAPCS rule C.2.vfp)
for (unsigned regNo = 0; regNo < 16; ++regNo)
State.AllocateReg(SRegList[regNo]);
// Register allocation failed, we'll be needing the stack
unsigned Size = LocVT.getSizeInBits() / 8;
unsigned Align = std::min(Size, 8U);
if (LocVT == MVT::i32 && State.getNextStackOffset() == 0) {
// If nothing else has used the stack until this point, a non-HFA aggregate
// can be split between regs and stack.
unsigned RegIdx = State.getFirstUnallocated(RegList);
for (auto &It : PendingMembers) {
if (RegIdx >= RegList.size())
It.convertToMem(State.AllocateStack(Size, Size));
else
It.convertToReg(State.AllocateReg(RegList[RegIdx++]));
for (auto It : PendingHAMembers) {
State.addLoc(It);
}
PendingMembers.clear();
return true;
} else if (LocVT != MVT::i32)
RegList = SRegList;
// Mark all regs as unavailable (AAPCS rule C.2.vfp for VFP, C.6 for core)
for (auto Reg : RegList)
State.AllocateReg(Reg);
for (auto &It : PendingMembers) {
It.convertToMem(State.AllocateStack(Size, Align));
State.addLoc(It);
// After the first item has been allocated, the rest are packed as tightly
// as possible. (E.g. an incoming i64 would have starting Align of 8, but
// we'll be allocating a bunch of i32 slots).
Align = Size;
}
// All pending members have now been allocated
PendingHAMembers.clear();
}
PendingMembers.clear();
// This will be allocated by the last member of the HA
// This will be allocated by the last member of the aggregate
return true;
}

2
lib/Target/ARM/ARMCallingConv.td
View File

@@ -175,7 +175,7 @@ def CC_ARM_AAPCS_VFP : CallingConv<[
CCIfType<[v2i64, v4i32, v8i16, v16i8, v4f32], CCBitConvertToType<v2f64>>,
// HFAs are passed in a contiguous block of registers, or on the stack
CCIfConsecutiveRegs<CCCustom<"CC_ARM_AAPCS_Custom_HA">>,
CCIfConsecutiveRegs<CCCustom<"CC_ARM_AAPCS_Custom_Aggregate">>,
CCIfType<[v2f64], CCAssignToReg<[Q0, Q1, Q2, Q3]>>,
CCIfType<[f64], CCAssignToReg<[D0, D1, D2, D3, D4, D5, D6, D7]>>,

12
lib/Target/ARM/ARMISelLowering.cpp
View File

@@ -11363,7 +11363,9 @@ static bool isHomogeneousAggregate(Type *Ty, HABaseType &Base,
return (Members > 0 && Members <= 4);
}
/// \brief Return true if a type is an AAPCS-VFP homogeneous aggregate.
/// \brief Return true if a type is an AAPCS-VFP homogeneous aggregate or one of
/// [N x i32] or [N x i64]. This allows front-ends to skip emitting padding when
/// passing according to AAPCS rules.
bool ARMTargetLowering::functionArgumentNeedsConsecutiveRegisters(
Type *Ty, CallingConv::ID CallConv, bool isVarArg) const {
if (getEffectiveCallingConv(CallConv, isVarArg) !=
@@ -11372,7 +11374,9 @@ bool ARMTargetLowering::functionArgumentNeedsConsecutiveRegisters(
HABaseType Base = HA_UNKNOWN;
uint64_t Members = 0;
bool result = isHomogeneousAggregate(Ty, Base, Members);
DEBUG(dbgs() << "isHA: " << result << " "; Ty->dump());
return result;
bool IsHA = isHomogeneousAggregate(Ty, Base, Members);
DEBUG(dbgs() << "isHA: " << IsHA << " "; Ty->dump());
bool IsIntArray = Ty->isArrayTy() && Ty->getArrayElementType()->isIntegerTy();
return IsHA || IsIntArray;
}

101
test/CodeGen/ARM/aggregate-padding.ll Normal file
View File

@@ -0,0 +1,101 @@
; RUN: llc -mtriple=armv7-linux-gnueabihf %s -o - | FileCheck %s
; [2 x i64] should be contiguous when split (e.g. we shouldn't try to align all
; i32 components to 64 bits). Also makes sure i64 based types are properly
; aligned on the stack.
define i64 @test_i64_contiguous_on_stack([8 x double], float, i32 %in, [2 x i64] %arg) nounwind {
; CHECK-LABEL: test_i64_contiguous_on_stack:
; CHECK-DAG: ldr [[LO0:r[0-9]+]], [sp, #8]
; CHECK-DAG: ldr [[HI0:r[0-9]+]], [sp, #12]
; CHECK-DAG: ldr [[LO1:r[0-9]+]], [sp, #16]
; CHECK-DAG: ldr [[HI1:r[0-9]+]], [sp, #20]
; CHECK: adds r0, [[LO0]], [[LO1]]
; CHECK: adc r1, [[HI0]], [[HI1]]
%val1 = extractvalue [2 x i64] %arg, 0
%val2 = extractvalue [2 x i64] %arg, 1
%sum = add i64 %val1, %val2
ret i64 %sum
}
; [2 x i64] should try to use looks for 4 regs, not 8 (which might happen if the
; i64 -> i32, i32 split wasn't handled correctly).
define i64 @test_2xi64_uses_4_regs([8 x double], float, [2 x i64] %arg) nounwind {
; CHECK-LABEL: test_2xi64_uses_4_regs:
; CHECK-DAG: mov r0, r2
; CHECK-DAG: mov r1, r3
%val = extractvalue [2 x i64] %arg, 1
ret i64 %val
}
; An aggregate should be able to split between registers and stack if there is
; nothing else on the stack.
define i32 @test_aggregates_split([8 x double], i32, [4 x i32] %arg) nounwind {
; CHECK-LABEL: test_aggregates_split:
; CHECK: ldr [[VAL3:r[0-9]+]], [sp]
; CHECK: add r0, r1, [[VAL3]]
%val0 = extractvalue [4 x i32] %arg, 0
%val3 = extractvalue [4 x i32] %arg, 3
%sum = add i32 %val0, %val3
ret i32 %sum
}
; If an aggregate has to be moved entirely onto the stack, nothing should be
; able to use r0-r3 any more. Also checks that [2 x i64] properly aligned when
; it uses regs.
define i32 @test_no_int_backfilling([8 x double], float, i32, [2 x i64], i32 %arg) nounwind {
; CHECK-LABEL: test_no_int_backfilling:
; CHECK: ldr r0, [sp, #24]
ret i32 %arg
}
; Even if the argument was successfully allocated as reg block, there should be
; no backfillig to r1.
define i32 @test_no_int_backfilling_regsonly(i32, [1 x i64], i32 %arg) {
; CHECK-LABEL: test_no_int_backfilling_regsonly:
; CHECK: ldr r0, [sp]
ret i32 %arg
}
; If an aggregate has to be moved entirely onto the stack, nothing should be
; able to use r0-r3 any more.
define float @test_no_float_backfilling([7 x double], [4 x i32], i32, [4 x double], float %arg) nounwind {
; CHECK-LABEL: test_no_float_backfilling:
; CHECK: vldr s0, [sp, #40]
ret float %arg
}
; They're a bit pointless, but types like [N x i8] should work as well.
define i8 @test_i8_in_regs(i32, [3 x i8] %arg) {
; CHECK-LABEL: test_i8_in_regs:
; CHECK: add r0, r1, r3
%val0 = extractvalue [3 x i8] %arg, 0
%val2 = extractvalue [3 x i8] %arg, 2
%sum = add i8 %val0, %val2
ret i8 %sum
}
define i16 @test_i16_split(i32, i32, [3 x i16] %arg) {
; CHECK-LABEL: test_i16_split:
; CHECK: ldrh [[VAL2:r[0-9]+]], [sp]
; CHECK: add r0, r2, [[VAL2]]
%val0 = extractvalue [3 x i16] %arg, 0
%val2 = extractvalue [3 x i16] %arg, 2
%sum = add i16 %val0, %val2
ret i16 %sum
}
; Beware: on the stack each i16 still gets a 32-bit slot, the array is not
; packed.
define i16 @test_i16_forced_stack([8 x double], double, i32, i32, [3 x i16] %arg) {
; CHECK-LABEL: test_i16_forced_stack:
; CHECK-DAG: ldrh [[VAL0:r[0-9]+]], [sp, #8]
; CHECK-DAG: ldrh [[VAL2:r[0-9]+]], [sp, #16]
; CHECK: add r0, [[VAL0]], [[VAL2]]
%val0 = extractvalue [3 x i16] %arg, 0
%val2 = extractvalue [3 x i16] %arg, 2
%sum = add i16 %val0, %val2
ret i16 %sum
}