bool EdgeCaseAnalysis::AllUsesTruncate(MInstruction *m) { for (MUseIterator use = m->usesBegin(); use != m->usesEnd(); use++) { // See #809485 why this is allowed if (use->node()->isResumePoint()) continue; MDefinition *def = use->node()->toDefinition(); if (def->isTruncateToInt32()) continue; if (def->isBitAnd()) continue; if (def->isBitOr()) continue; if (def->isBitXor()) continue; if (def->isLsh()) continue; if (def->isRsh()) continue; if (def->isBitNot()) continue; if (def->isAdd() && def->toAdd()->isTruncated()) continue; if (def->isSub() && def->toSub()->isTruncated()) continue; // cannot use divide, since |truncate(int32(x/y) + int32(a/b)) != truncate(x/y+a/b)| return false; } return true; }
void MBasicBlock::assertUsesAreNotWithin(MUseIterator use, MUseIterator end) { #ifdef DEBUG for (; use != end; use++) { JS_ASSERT_IF(use->node()->isDefinition(), use->node()->toDefinition()->block()->id() < id()); } #endif }
static bool CheckMarkedAsUse(MInstruction *ins, MDefinition *operand) { for (MUseIterator i = operand->usesBegin(); i != operand->usesEnd(); i++) { if (i->node()->isDefinition()) { if (ins == i->node()->toDefinition()) return true; } } return false; }
int EdgeCaseAnalysis::AllUsesTruncate(MInstruction *m) { // If all uses truncate, the return value must be at least 1. If anything doesn't truncate // 0 is explicitly returned. int ret = 1; for (MUseIterator use = m->usesBegin(); use != m->usesEnd(); use++) { // See #809485 why this is allowed if (use->node()->isResumePoint()) continue; MDefinition *def = use->node()->toDefinition(); if (def->isTruncateToInt32()) continue; if (def->isBitAnd()) continue; if (def->isBitOr()) continue; if (def->isBitXor()) continue; if (def->isLsh()) continue; if (def->isRsh()) continue; if (def->isBitNot()) continue; if (def->isAdd() && def->toAdd()->isTruncated()) { ret = Max(ret, def->toAdd()->isTruncated() + 1); continue; } if (def->isSub() && def->toSub()->isTruncated()) { ret = Max(ret, def->toSub()->isTruncated() + 1); continue; } // cannot use divide, since |truncate(int32(x/y) + int32(a/b)) != truncate(x/y+a/b)| return 0; } return ret; }
static inline bool NeedNegativeZeroCheck(MDefinition *def) { // Test if all uses have the same symantic for -0 and 0 for (MUseIterator use = def->usesBegin(); use != def->usesEnd(); use++) { if (use->node()->isResumePoint()) return true; MDefinition *use_def = use->node()->toDefinition(); switch (use_def->op()) { case MDefinition::Op_Add: { // x + y gives -0, when both x and y are -0 // - When other operand can't produce -0 (i.e. all opcodes, except Mul/Div/ToInt32) // Remove negative zero check on this operand // - When both operands can produce -0 (both Mul/Div/ToInt32 opcode) // We can remove the check eagerly on this operand. MDefinition *operand = use_def->getOperand(0); if (operand == def) { operand = use_def->getOperand(1); // Don't remove check when both operands are same definition // As removing it from one operand, will remove it from both. if (operand == def) return true; } // Check if check is possibly eagerly removed on other operand // and don't remove check eagerly on this operand in that case. if (operand->isMul()) { MMul *mul = operand->toMul(); if (!mul->canBeNegativeZero()) return true; } else if (operand->isDiv()) { MDiv *div = operand->toDiv(); if (!div->canBeNegativeZero()) return true; } else if (operand->isToInt32()) { MToInt32 *int32 = operand->toToInt32(); if (!int32->canBeNegativeZero()) return true; } else if (operand->isPhi()) { return true; } break; } case MDefinition::Op_StoreElement: case MDefinition::Op_StoreElementHole: case MDefinition::Op_LoadElement: case MDefinition::Op_LoadElementHole: case MDefinition::Op_LoadTypedArrayElement: case MDefinition::Op_LoadTypedArrayElementHole: case MDefinition::Op_CharCodeAt: case MDefinition::Op_Mod: case MDefinition::Op_Sub: // Only allowed to remove check when definition is the second operand if (use_def->getOperand(0) == def) return true; if (use_def->numOperands() > 2) { for (size_t i = 2; i < use_def->numOperands(); i++) { if (use_def->getOperand(i) == def) return true; } } break; case MDefinition::Op_BoundsCheck: // Only allowed to remove check when definition is the first operand if (use_def->getOperand(1) == def) return true; break; case MDefinition::Op_ToString: case MDefinition::Op_FromCharCode: case MDefinition::Op_TableSwitch: case MDefinition::Op_Compare: case MDefinition::Op_BitAnd: case MDefinition::Op_BitOr: case MDefinition::Op_BitXor: case MDefinition::Op_Abs: // Always allowed to remove check. No matter which operand. break; default: return true; } } return false; }