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ppc: [liftoff] optimize FillStackSlotsWithZero

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Change-Id: Ic2576da8adff6935758ecae14ce5441d8af6428b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3075123
Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/master@{#76121}
This commit is contained in:
Junliang Yan 2021-08-05 08:23:31 -04:00 committed by V8 LUCI CQ
parent c5faf5bab1
commit aba716e6df
1 changed files with 19 additions and 19 deletions
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38
src/wasm/baseline/ppc/liftoff-assembler-ppc.h
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@ -691,40 +691,40 @@ void LiftoffAssembler::FillI64Half(Register, int offset, RegPairHalf) {
void LiftoffAssembler::FillStackSlotsWithZero(int start, int size) {
DCHECK_LT(0, size);
DCHECK_EQ(0, size % 4);
DCHECK_EQ(0, size % 8);
RecordUsedSpillOffset(start + size);
// We need a zero reg. Always use r0 for that, and push it before to restore
// its value afterwards.
push(r0);
mov(r0, Operand(0));
if (size <= 36) {
// Special straight-line code for up to nine words. Generates one
// instruction per word.
for (int offset = 4; offset <= size; offset += 4) {
StoreU64(r0, liftoff::GetHalfStackSlot(start + offset, kLowWord));
mov(ip, Operand::Zero());
uint32_t remainder = size;
for (; remainder >= kStackSlotSize; remainder -= kStackSlotSize) {
StoreU64(ip, liftoff::GetStackSlot(start + remainder), r0);
}
DCHECK(remainder == 4 || remainder == 0);
if (remainder) {
StoreU32(ip, liftoff::GetStackSlot(start + remainder), r0);
}
} else {
// General case for bigger counts (9 instructions).
// Use r4 for start address (inclusive), r5 for end address (exclusive).
push(r4);
push(r5);
SubS64(r4, fp, Operand(start + size), r0);
SubS64(r5, fp, Operand(start), r0);
Label loop;
push(r4);
mov(r4, Operand(size / kSystemPointerSize));
mtctr(r4);
SubS64(r4, fp, Operand(start + size + kSystemPointerSize), r0);
mov(r0, Operand::Zero());
bind(&loop);
StoreU64(r0, MemOperand(r0));
addi(r0, r0, Operand(kSystemPointerSize));
CmpS64(r4, r5);
bne(&loop);
StoreU64WithUpdate(r0, MemOperand(r4, kSystemPointerSize));
bdnz(&loop);
pop(r4);
pop(r5);
}
pop(r0);
}
#define SIGN_EXT(r) extsw(r, r)