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Merged: ppc: Don't emit cnttzd, cnttzw if Power proc. version is less than 9
Revision: 937d44e9ec11eb28a076ed69f5daf296cb146b74

Merged: ppc: Don't emit unsupported isns on Power8 arch
Revision: 2b01c8286b734b54fd5e020024c1d67e075f1969

Merged: PPC: Optimize count of trailing zeros on P8 and below
Revision: 0bb4006648ea5de29f775970905d47b727e01688

NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
[email protected]

Bug: v8:12404
Change-Id: I18c693794d72236fc1010950b0d89aa626d969b9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3289930
Reviewed-by: Junliang Yan <[email protected]>
Commit-Queue: Lutz Vahl <[email protected]>
Cr-Commit-Position: refs/branch-heads/9.7@{#15}
Cr-Branched-From: 49162da-refs/heads/9.7.106@{#1}
Cr-Branched-From: a7e9b8f-refs/heads/main@{#77674}
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Vasili Skurydzin authored and V8 LUCI CQ committed Nov 22, 2021
1 parent 31efda6 commit 5f980ae
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Showing 3 changed files with 193 additions and 8 deletions.
122 changes: 116 additions & 6 deletions src/codegen/ppc/macro-assembler-ppc.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -2818,19 +2818,55 @@ void TurboAssembler::DivU32(Register dst, Register src, Register value, OEBit s,
}

void TurboAssembler::ModS64(Register dst, Register src, Register value) {
modsd(dst, src, value);
if (CpuFeatures::IsSupported(PPC_9_PLUS)) {
modsd(dst, src, value);
} else {
Register scratch = GetRegisterThatIsNotOneOf(dst, src, value);
Push(scratch);
divd(scratch, src, value);
mulld(scratch, scratch, value);
sub(dst, src, scratch);
Pop(scratch);
}
}

void TurboAssembler::ModU64(Register dst, Register src, Register value) {
modud(dst, src, value);
if (CpuFeatures::IsSupported(PPC_9_PLUS)) {
modud(dst, src, value);
} else {
Register scratch = GetRegisterThatIsNotOneOf(dst, src, value);
Push(scratch);
divdu(scratch, src, value);
mulld(scratch, scratch, value);
sub(dst, src, scratch);
Pop(scratch);
}
}

void TurboAssembler::ModS32(Register dst, Register src, Register value) {
modsw(dst, src, value);
if (CpuFeatures::IsSupported(PPC_9_PLUS)) {
modsw(dst, src, value);
} else {
Register scratch = GetRegisterThatIsNotOneOf(dst, src, value);
Push(scratch);
divw(scratch, src, value);
mullw(scratch, scratch, value);
sub(dst, src, scratch);
Pop(scratch);
}
extsw(dst, dst);
}
void TurboAssembler::ModU32(Register dst, Register src, Register value) {
moduw(dst, src, value);
if (CpuFeatures::IsSupported(PPC_9_PLUS)) {
moduw(dst, src, value);
} else {
Register scratch = GetRegisterThatIsNotOneOf(dst, src, value);
Push(scratch);
divwu(scratch, src, value);
mullw(scratch, scratch, value);
sub(dst, src, scratch);
Pop(scratch);
}
ZeroExtWord32(dst, dst);
}

Expand Down Expand Up @@ -3732,14 +3768,88 @@ void TurboAssembler::CountLeadingZerosU64(Register dst, Register src, RCBit r) {
cntlzd(dst, src, r);
}

#define COUNT_TRAILING_ZEROES_SLOW(max_count, scratch1, scratch2) \
Label loop, done; \
li(scratch1, Operand(max_count)); \
mtctr(scratch1); \
mr(scratch1, src); \
li(dst, Operand::Zero()); \
bind(&loop); /* while ((src & 1) == 0) */ \
andi(scratch2, scratch1, Operand(1)); \
bne(&done, cr0); \
srdi(scratch1, scratch1, Operand(1)); /* src >>= 1;*/ \
addi(dst, dst, Operand(1)); /* dst++ */ \
bdnz(&loop); \
bind(&done);
void TurboAssembler::CountTrailingZerosU32(Register dst, Register src,
Register scratch1, Register scratch2,
RCBit r) {
cnttzw(dst, src, r);
if (CpuFeatures::IsSupported(PPC_9_PLUS)) {
cnttzw(dst, src, r);
} else {
COUNT_TRAILING_ZEROES_SLOW(32, scratch1, scratch2);
}
}

void TurboAssembler::CountTrailingZerosU64(Register dst, Register src,
Register scratch1, Register scratch2,
RCBit r) {
cnttzd(dst, src, r);
if (CpuFeatures::IsSupported(PPC_9_PLUS)) {
cnttzd(dst, src, r);
} else {
COUNT_TRAILING_ZEROES_SLOW(64, scratch1, scratch2);
}
}
#undef COUNT_TRAILING_ZEROES_SLOW

void TurboAssembler::ClearByteU64(Register dst, int byte_idx) {
CHECK(0 <= byte_idx && byte_idx <= 7);
int shift = byte_idx*8;
rldicl(dst, dst, shift, 8);
rldicl(dst, dst, 64-shift, 0);
}

void TurboAssembler::ReverseBitsU64(Register dst, Register src,
Register scratch1, Register scratch2) {
ByteReverseU64(dst, src);
for (int i = 0; i < 8; i++) {
ReverseBitsInSingleByteU64(dst, dst, scratch1, scratch2, i);
}
}

void TurboAssembler::ReverseBitsU32(Register dst, Register src,
Register scratch1, Register scratch2) {
ByteReverseU32(dst, src);
for (int i = 4; i < 8; i++) {
ReverseBitsInSingleByteU64(dst, dst, scratch1, scratch2, i);
}
}

// byte_idx=7 refers to least significant byte
void TurboAssembler::ReverseBitsInSingleByteU64(Register dst, Register src,
Register scratch1,
Register scratch2,
int byte_idx) {
CHECK(0 <= byte_idx && byte_idx <= 7);
int j = byte_idx;
// zero all bits of scratch1
li(scratch2, Operand(0));
for (int i = 0; i <= 7; i++) {
// zero all bits of scratch1
li(scratch1, Operand(0));
// move bit (j+1)*8-i-1 of src to bit j*8+i of scratch1, erase bits
// (j*8+i+1):end of scratch1
int shift = 7 - (2*i);
if (shift < 0) shift += 64;
rldicr(scratch1, src, shift, j*8+i);
// erase bits start:(j*8-1+i) of scratch1 (inclusive)
rldicl(scratch1, scratch1, 0, j*8+i);
// scratch2 = scratch2|scratch1
orx(scratch2, scratch2, scratch1);
}
// clear jth byte of dst and insert jth byte of scratch2
ClearByteU64(dst, j);
orx(dst, dst, scratch2);
}

} // namespace internal
Expand Down
15 changes: 13 additions & 2 deletions src/codegen/ppc/macro-assembler-ppc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -263,8 +263,19 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {

void CountLeadingZerosU32(Register dst, Register src, RCBit r = LeaveRC);
void CountLeadingZerosU64(Register dst, Register src, RCBit r = LeaveRC);
void CountTrailingZerosU32(Register dst, Register src, RCBit r = LeaveRC);
void CountTrailingZerosU64(Register dst, Register src, RCBit r = LeaveRC);
void CountTrailingZerosU32(Register dst, Register src, Register scratch1 = ip,
Register scratch2 = r0, RCBit r = LeaveRC);
void CountTrailingZerosU64(Register dst, Register src, Register scratch1 = ip,
Register scratch2 = r0, RCBit r = LeaveRC);

void ClearByteU64(Register dst, int byte_idx);
void ReverseBitsU64(Register dst, Register src, Register scratch1,
Register scratch2);
void ReverseBitsU32(Register dst, Register src, Register scratch1,
Register scratch2);
void ReverseBitsInSingleByteU64(Register dst, Register src,
Register scratch1, Register scratch2,
int byte_idx);

void AddF64(DoubleRegister dst, DoubleRegister lhs, DoubleRegister rhs,
RCBit r = LeaveRC);
Expand Down
64 changes: 64 additions & 0 deletions test/unittests/assembler/turbo-assembler-ppc-unittest.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,70 @@ TEST_F(TurboAssemblerTest, TestCheck) {
ASSERT_DEATH_IF_SUPPORTED({ f.Call(17); }, "abort: no reason");
}

TEST_F(TurboAssemblerTest, ReverseBitsU64) {
struct {
uint64_t expected; uint64_t input;
} values[] = {
{0x0000000000000000, 0x0000000000000000},
{0xffffffffffffffff, 0xffffffffffffffff},
{0x8000000000000000, 0x0000000000000001},
{0x0000000000000001, 0x8000000000000000},
{0x800066aa22cc4488, 0x1122334455660001},
{0x1122334455660001, 0x800066aa22cc4488},
{0xffffffff00000000, 0x00000000ffffffff},
{0x00000000ffffffff, 0xffffffff00000000},
{0xff01020304050607, 0xe060a020c04080ff},
{0xe060a020c04080ff, 0xff01020304050607},
};
auto buffer = AllocateAssemblerBuffer();
TurboAssembler tasm(isolate(), AssemblerOptions{}, CodeObjectRequired::kNo,
buffer->CreateView());
__ set_root_array_available(false);
__ set_abort_hard(true);
__ Push(r4, r5);
__ ReverseBitsU64(r3, r3, r4, r5);
__ Pop(r4, r5);
__ Ret();
CodeDesc desc;
tasm.GetCode(isolate(), &desc);
buffer->MakeExecutable();
auto f = GeneratedCode<uint64_t, uint64_t>::FromBuffer(isolate(),
buffer->start());
for (unsigned int i=0; i < (sizeof(values) / sizeof(values[0])); i++) {
CHECK_EQ(values[i].expected, f.Call(values[i].input));
}
}

TEST_F(TurboAssemblerTest, ReverseBitsU32) {
struct {
uint64_t expected; uint64_t input;
} values[] = {
{0x00000000, 0x00000000},
{0xffffffff, 0xffffffff},
{0x00000001, 0x80000000},
{0x80000000, 0x00000001},
{0x22334455, 0xaa22cc44},
{0xaa22cc44, 0x22334455},
};
auto buffer = AllocateAssemblerBuffer();
TurboAssembler tasm(isolate(), AssemblerOptions{}, CodeObjectRequired::kNo,
buffer->CreateView());
__ set_root_array_available(false);
__ set_abort_hard(true);
__ Push(r4, r5);
__ ReverseBitsU32(r3, r3, r4, r5);
__ Pop(r4, r5);
__ Ret();
CodeDesc desc;
tasm.GetCode(isolate(), &desc);
buffer->MakeExecutable();
auto f = GeneratedCode<uint64_t, uint64_t>::FromBuffer(isolate(),
buffer->start());
for (unsigned int i=0; i < (sizeof(values) / sizeof(values[0])); i++) {
CHECK_EQ(values[i].expected, f.Call(values[i].input));
}
}

#undef __

} // namespace internal
Expand Down

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