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[AArch64] Optimize FPR pushing and popping. 

Previously on FPR pushing and popping we would do a single STR/LDR per quad FPR we wanted to push/pop.
In most of our cases when we are pushing and popping VFP registers they will be consecutive registers that will save more efficiently using the NEON
loadstores that can do up to four quad registers.
So this can potentially cutting instructions down to ~1/4th the amount of instructions if the registers are all consecutive.

On the Cortex-A57 this is basically just an icache improvement, but on the Nvidia Denver this may be optimized to be more efficient. Either way it's a
win.
This commit is contained in:
Ryan Houdek 2015-02-28 04:39:15 -06:00
parent c792d45d89
commit 8b8310d28c
2 changed files with 139 additions and 11 deletions
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133
Source/Core/Common/Arm64Emitter.cpp
View File

@ -1891,6 +1891,27 @@ void ARM64FloatEmitter::EmitLoadStoreMultipleStructure(u32 size, bool L, u32 opc
(encoded_size << 10) | (Rn << 5) | Rt);
}
void ARM64FloatEmitter::EmitLoadStoreMultipleStructurePost(u32 size, bool L, u32 opcode, ARM64Reg Rt, ARM64Reg Rn, ARM64Reg Rm)
{
bool quad = IsQuad(Rt);
u32 encoded_size = 0;
if (size == 16)
encoded_size = 1;
else if (size == 32)
encoded_size = 2;
else if (size == 64)
encoded_size = 3;
Rt = DecodeReg(Rt);
Rn = DecodeReg(Rn);
Rm = DecodeReg(Rm);
Write32((quad << 30) | (0b11001 << 23) | (L << 22) | (Rm << 16) | (opcode << 12) | \
(encoded_size << 10) | (Rn << 5) | Rt);
}
void ARM64FloatEmitter::EmitScalar1Source(bool M, bool S, u32 type, u32 opcode, ARM64Reg Rd, ARM64Reg Rn)
{
_assert_msg_(DYNA_REC, !IsQuad(Rd), "%s doesn't support vector!", __FUNCTION__);
@ -2234,6 +2255,22 @@ void ARM64FloatEmitter::LD1(u8 size, u8 count, ARM64Reg Rt, ARM64Reg Rn)
opcode = 0b0010;
EmitLoadStoreMultipleStructure(size, 1, opcode, Rt, Rn);
}
void ARM64FloatEmitter::LD1(u8 size, u8 count, IndexType type, ARM64Reg Rt, ARM64Reg Rn, ARM64Reg Rm)
{
_assert_msg_(DYNA_REC, !(count == 0 || count > 4), "%s must have a count of 1 to 4 registers!", __FUNCTION__);
_assert_msg_(DYNA_REC, type == INDEX_POST, "%s only supports post indexing!", __FUNCTION__);
u32 opcode = 0;
if (count == 1)
opcode = 0b111;
else if (count == 2)
opcode = 0b1010;
else if (count == 3)
opcode = 0b0110;
else if (count == 4)
opcode = 0b0010;
EmitLoadStoreMultipleStructurePost(size, 1, opcode, Rt, Rn, Rm);
}
void ARM64FloatEmitter::ST1(u8 size, u8 count, ARM64Reg Rt, ARM64Reg Rn)
{
_assert_msg_(DYNA_REC, !(count == 0 || count > 4), "%s must have a count of 1 to 4 registers!", __FUNCTION__);
@ -2248,6 +2285,22 @@ void ARM64FloatEmitter::ST1(u8 size, u8 count, ARM64Reg Rt, ARM64Reg Rn)
opcode = 0b0010;
EmitLoadStoreMultipleStructure(size, 0, opcode, Rt, Rn);
}
void ARM64FloatEmitter::ST1(u8 size, u8 count, IndexType type, ARM64Reg Rt, ARM64Reg Rn, ARM64Reg Rm)
{
_assert_msg_(DYNA_REC, !(count == 0 || count > 4), "%s must have a count of 1 to 4 registers!", __FUNCTION__);
_assert_msg_(DYNA_REC, type == INDEX_POST, "%s only supports post indexing!", __FUNCTION__);
u32 opcode = 0;
if (count == 1)
opcode = 0b111;
else if (count == 2)
opcode = 0b1010;
else if (count == 3)
opcode = 0b0110;
else if (count == 4)
opcode = 0b0010;
EmitLoadStoreMultipleStructurePost(size, 0, opcode, Rt, Rn, Rm);
}
// Scalar - 1 Source
void ARM64FloatEmitter::FABS(ARM64Reg Rd, ARM64Reg Rn)
@ -2761,22 +2814,94 @@ void ARM64FloatEmitter::FMUL(u8 size, ARM64Reg Rd, ARM64Reg Rn, ARM64Reg Rm, u8
void ARM64FloatEmitter::ABI_PushRegisters(BitSet32 registers)
{
bool bundled_loadstore = false;
for (int i = 0; i < 32; ++i)
{
if (!registers[i])
continue;
int count = 0;
while (++count < 4 && (i + count) < 32 && registers[i + count]) {}
if (count > 1)
{
bundled_loadstore = true;
break;
}
}
if (!bundled_loadstore)
{
for (auto it : registers)
STR(128, INDEX_PRE, (ARM64Reg)(Q0 + it), SP, -16);
}
else
{
int num_regs = registers.Count();
// Violating the AAPCS64 never felt so right.
m_emit->SUB(SP, SP, num_regs * 16);
for (int i = 0; i < 32; ++i)
{
if (!registers[i])
continue;
int count = 0;
// 0 = true
// 1 < 4 && registers[i + 1] true!
// 2 < 4 && registers[i + 2] true!
// 3 < 4 && registers[i + 3] true!
// 4 < 4 && registers[i + 4] false!
while (++count < 4 && (i + count) < 32 && registers[i + count]) {}
ST1(64, count, INDEX_POST, (ARM64Reg)(Q0 + i), SP);
i += count - 1;
}
m_emit->SUB(SP, SP, num_regs * 16);
}
}
void ARM64FloatEmitter::ABI_PopRegisters(BitSet32 registers, BitSet32 ignore_mask)
void ARM64FloatEmitter::ABI_PopRegisters(BitSet32 registers)
{
bool bundled_loadstore = false;
for (int i = 0; i < 32; ++i)
{
if (!registers[i])
continue;
int count = 0;
while (++count < 4 && (i + count) < 32 && registers[i + count]) {}
if (count > 1)
{
bundled_loadstore = true;
break;
}
}
if (!bundled_loadstore)
{
for (int i = 31; i >= 0; --i)
{
if (!registers[i])
continue;
if (ignore_mask[i])
m_emit->ADD(SP, SP, 16);
else
LDR(128, INDEX_POST, (ARM64Reg)(Q0 + i), SP, 16);
}
}
else
{
for (int i = 0; i < 32; ++i)
{
if (!registers[i])
continue;
int count = 0;
while (++count < 4 && (i + count) < 32 && registers[i + count]) {}
LD1(64, count, INDEX_POST, (ARM64Reg)(Q0 + i), SP);
i += count - 1;
}
}
}
}

5
Source/Core/Common/Arm64Emitter.h
View File

@ -658,7 +658,9 @@ public:
// Loadstore multiple structure
void LD1(u8 size, u8 count, ARM64Reg Rt, ARM64Reg Rn);
void LD1(u8 size, u8 count, IndexType type, ARM64Reg Rt, ARM64Reg Rn, ARM64Reg Rm = SP);
void ST1(u8 size, u8 count, ARM64Reg Rt, ARM64Reg Rn);
void ST1(u8 size, u8 count, IndexType type, ARM64Reg Rt, ARM64Reg Rn, ARM64Reg Rm = SP);
// Scalar - 1 Source
void FABS(ARM64Reg Rd, ARM64Reg Rn);
@ -748,7 +750,7 @@ public:
// ABI related
void ABI_PushRegisters(BitSet32 registers);
void ABI_PopRegisters(BitSet32 registers, BitSet32 ignore_mask = BitSet32(0));
void ABI_PopRegisters(BitSet32 registers);
private:
ARM64XEmitter* m_emit;
@ -770,6 +772,7 @@ private:
void EmitScalarImm(bool M, bool S, u32 type, u32 imm5, ARM64Reg Rd, u32 imm);
void EmitShiftImm(bool U, u32 immh, u32 immb, u32 opcode, ARM64Reg Rd, ARM64Reg Rn);
void EmitLoadStoreMultipleStructure(u32 size, bool L, u32 opcode, ARM64Reg Rt, ARM64Reg Rn);
void EmitLoadStoreMultipleStructurePost(u32 size, bool L, u32 opcode, ARM64Reg Rt, ARM64Reg Rn, ARM64Reg Rm);
void EmitScalar1Source(bool M, bool S, u32 type, u32 opcode, ARM64Reg Rd, ARM64Reg Rn);
void EmitVectorxElement(bool U, u32 size, bool L, u32 opcode, bool H, ARM64Reg Rd, ARM64Reg Rn, ARM64Reg Rm);
void EmitLoadStoreUnscaled(u32 size, u32 op, ARM64Reg Rt, ARM64Reg Rn, s32 imm);